Sample records for weight bearing gait

  1. The Effects of Additional Action Observational Training for Functional Electrical Stimulation Treatment on Weight Bearing, Stability and Gait Velocity of Hemiplegic Patients

    PubMed Central

    Park, Chang-Sik; Kang, Kwon-Young

    2013-01-01

    [Purpose] The purpose of this study was to evaluate the functional effects of additional action observational training for functional electrical stimulation treatment on weight bearing, stability and gait velocity of hemiplegic patients. [Subjects and Methods] Twenty subjects were randomized into two groups. Subjects more than six months post-stroke participated. Balance and gait velocity were measured at the baseline, and after six weeks of treatment. Both groups received functional electrical stimulation treatment. The experimental group additionally received action observational training. The paired t-test was used to analyze differences in the outcome measures between before and after the intervention. The difference between the groups was compared using the independent t-test. [Results] The experimental group showed significant increases in weight bearing (anterior·posterior, right·left) on the affected side, stability index and gait velocity. The control group showed only a significant increase in anterior·posterior weight bearing on the affected side. Moreover, according to the comparison of training effects between in the two groups, the variables of anterior·posterior weight bearing, stability index and gait velocity revealed a statistically significant difference. [Conclusion] Additional action observational training for functional electrical stimulation treatment should be considered as a therapeutic method in physical therapy for the improvement of weight bearing, stability index and gait velocity of hemiplegic patients. PMID:24259939

  2. Relationship between the weight-bearing ratio on the affected lower extremity and gait ability using a portable electronic foot sensor shoe (Step Aid®) in hemiplegic stroke patients

    PubMed Central

    Itotani, Keisuke; Murakami, Masahito; Itotani, Motoko; Nagai, Atsushi; Imabori, Yuzo; Fujimoto, Kazuyuki; Tanaka, Mamoru; Kato, Junichi

    2015-01-01

    [Purpose] This study investigated the association between the weight-bearing ratio (WBR) and gait ability of a paretic lower limb while walking using a shoe-type load-measuring apparatus. [Subjects] The Subjects comprised 17 stroke patients who were classified into the following two groups: the independent walking group, and the non-independent walking group. [Methods] The 10-m walking time (inside and outside parallel bars) and the Berg Balance Scale (BBS) were measured. The WBR of the paretic lower limb was measured during static standing and while walking inside and outside parallel bars, and the coefficient of variation (CV) was calculated. WBR was evaluated using the Step Aid. [Results] The BBS and WBR were significantly decreased in the non-independent walking group, while the 10-m walking time and the CV were significantly increased in the non-independent walking group. [Conclusion] The CV and WBR of a paretic lower limb while walking appear to be important indices of achievement of independent gait in hemiplegic stroke patients, and they may be used in gait rehabilitation for diseases requiring weight-bearing training to follow the course of training using a shoe-type load-measuring apparatus. PMID:25729160

  3. Fixed-Bearing Total Ankle Replacement (TAR) Improves Gait Function

    MedlinePLUS

    ... positive short-term results A study of gait mechanics in patients who underwent total ankle replacement (TAR) ... improvement in nearly all measured parameters of gait mechanics (measured preoperatively, 1 year postoperative, and 2 years ...

  4. Measuring Bearing Wear Via Weight Loss

    NASA Technical Reports Server (NTRS)

    Keba, John E.; Moore, Richard S.

    1989-01-01

    Wear in critical parts of bearings measured via amounts of weight lost during use. Technique applicable in general to bearings made of nonporous materials. Weight-loss measurements easier, faster, more precise, and less likely to damage measured parts. Weight-loss measurements performed in clean rooms and under constraint of extreme cleanliness for compatability with liquid oxygen.

  5. [The clinical effect of lateral wedge on hemiplegic weight bearing].

    PubMed

    Kakou, Hiroaki; Nagao, Yoko; Omine, Saburo; Ochi, Mitsuhiro; Wada, Futoshi; Hachisuka, Kenji; Togami, Hidenori

    2003-12-01

    The purpose of this study was to investigate the influence of the lateral wedge on asymmetrical weight bearing and posture in hemiplegic gait. The subjects were 2-female and 4-male moderate stroke patients, average age 54 +/- 6 yr. The time from onset was 127 +/- 69.7 days. A 7 mm-thick wedged insole was applied to the affected side for a week. Before and after that, the vertical ground reaction force, single supporting period and side movement of the trunk were recorded during walking. As a result, we found that the vertical ground reaction ratio and single supporting period ratio of the affected side (affected/unaffected) were significantly increased (P < 0.05), and also that the lateral sway of the trunk was remarkably decreased (P < 0.05). Our results indicate that the application of the lateral wedge for a week improved asymmetrical weight bearing and gait ability in moderate hemiplegic patients. Also we believe that a randomly sampled comparison study should be performed in the near future. PMID:14692346

  6. Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

    PubMed Central

    Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

    2015-01-01

    [Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke. PMID:26157272

  7. Additional weight load increases freezing of gait episodes in Parkinson's disease; an experimental study.

    PubMed

    Mensink, Senja H G; Nonnekes, Jorik; van Bon, Geert; Snijders, Anke H; Duysens, Jacques; Weerdesteyn, Vivian; Bloem, Bastiaan R; Oude Nijhuis, Lars B

    2014-05-01

    Freezing of gait is an episodic gait disorder,characterized by the inability to generate effective forward stepping movements. The pathophysiology underlying freezing of gait remains insufficiently understood, and this hampers the development of better treatment strategies.Preliminary evidence suggests that impaired force control during walking may contribute to freezing episodes, with difficulty to unload the swing leg and initiate the swing phase. Here, we used external loading to manipulate force control and to investigate its influence on freezing of gait.Twelve Parkinson's disease patients with freezing of gait performed three contrasting tasks: (1) loaded gait while wearing a belt fortified with lead weights; (2) weight supported gait using a parachute harness connected to a rigid metal cable running above the gait trajectory; and (3)normal gait. Gait tasks were used to provoke freezing episodes, including rapid 360° turns. Freezing episodes were quantified using blinded, videotaped clinical assessment. Furthermore, ground reaction forces and body kinematics were recorded. Loading significantly increased the mean number of freezing episodes per trial compared to the normal gait condition (P<0.05), but the effect of weight support was not consistent. Loading particularly increased the number of freezing episodes during rapid short steps. Step length was significantly smaller during loaded gait compared to normal gait (P<0.05), but changes in anticipatory postural adjustments were not different.Our results may point to impaired force control playing a key role in freezing of gait. Future studies should further investigate the mechanism, i.e., the contribution of deficient load feedback, and evaluate which forms of weight support might offer treatment opportunities. PMID:24658705

  8. Regional differences in trabecular BMD and micro-architecture of weight-bearing bone under habitual gait loading--a pQCT and microCT study in human cadavers.

    PubMed

    Lai, Y M; Qin, L; Yeung, H Y; Lee, K K H; Chan, K M

    2005-08-01

    This study used both multi-slice pQCT and microCT to investigate regional changes in bone mineral density and structural parameters in the ultradistal tibia and in the mid-femoral neck under habitual gait loading. Twenty cadavers with 2 females and 18 males aged 70.8 +/- 8.5 were used in this study. Seventy-two cylindrical bone cores with 5 mm in diameter and 10 mm in length from the anterior/posterior and superior/inferior regions were obtained from ultradistal tibia and mid-femur neck, respectively, so that their differences in terms of volumetric trabecular bone mineral density (tBMD) as well as micro-architectural parameters could be studied. The results showed that the mean volumetric tBMD at both the organ (including the bone marrow spaces) and tissue levels (excluding the bone marrow spaces) were a 49.2% and 28.3%, respectively, lower in the anterior bone cores than in the posterior bone cores from the ultradistal tibia (P < 0.01). MicroCT measurements on BV/TV, BS/TV, Tb.N, Tb.Th, and DA were found to be on average of 33.5%, 23.6%, 9.1%, 18.0%, and 14.6%, respectively, lower in the anterior trabecular bone cores (P < 0.001), while Tb.Sp and SMI were 12.5% and 29.3%, respectively, higher in the anterior trabecular bone cores (P < 0.01). No significant difference in micro-architectural parameters was found in the trabecular bone cores obtained from mid-femoral neck, except that the mean DA of the inferior bone cores was significantly higher by 30.1% than that of the superior bone cores (P = 0.01). A statistically significant linear relationship with the correlation coefficient, ranging from 0.37 to 0.94 and -0.62 to -0.85, respectively, was shown between the tBMD at the organ level and all of the micro-architectural parameters (P < 0.05). We suggest that dynamic loading changes during the striking of the heel in normal gait, as well as the peaks of the hip joint reaction force occur during the heel strike and before toe off positions in the lifetime of the subject may account for such regional differences in BMD and micro-architecture. The findings from the correlation study also suggest that, apart from BMD, the micro-architecture may exhibit adaptation in response to such excessive loading. PMID:15961358

  9. Side by side treadmill walking reduces gait asymmetry induced by unilateral ankle weight.

    PubMed

    Nessler, Jeff A; Gutierrez, Veronica; Werner, Judea; Punsalan, Andrew

    2015-06-01

    Asymmetric gait is a hallmark of many neurological and musculoskeletal conditions. This behavior is often the result of a decrease in the stability of interlimb coordination, and synchronization to external signals such as auditory cuing or another walking individual may be helpful for altering abnormal movement patterns. The purpose of this study was to investigate the interaction between interlimb coordination and unintentional, interpersonal synchronization of gait in healthy individuals in response to unilateral ankle loading. Fifty participants completed four trials while walking on a motorized treadmill: (1) by themselves, (2) with a partner on an adjacent treadmill, (3) by themselves with additional weight applied unilaterally to their right ankle, and (4) with both a partner and unilateral weight. As expected, the addition of unilateral weight increased asymmetry according to several spatiotemporal measures of gait, but the presence of a partner on an adjacent treadmill significantly reduced this effect. Further, the amount of unintentional, interpersonal synchronization among pairings was relatively unaffected by the addition of ankle weight to one of the partners. All pairings realized a beneficial effect on asymmetrical gait but this effect was greater for pairings that consistently synchronized unintentionally. These results suggest that side by side walking might be an effective approach for influencing bilateral coordination of gait and may hold insight for understanding gait asymmetry and interlimb movement variability. PMID:25744595

  10. Kinematic and kinetic changes in obese gait in bariatric surgery-induced weight loss.

    PubMed

    Vartiainen, Paavo; Bragge, Timo; Lyytinen, Tarja; Hakkarainen, Marko; Karjalainen, Pasi A; Arokoski, Jari P

    2012-06-26

    This study examines the effects of a radical bariatric surgery-induced weight loss on the gait of obese subjects. We performed a three-dimensional motion analysis of lower limbs, and collected force platform data in the gait laboratory to calculate knee and hip joint moments. Subjects (n=13) performed walking trials in the laboratory before and 8.8 months (SD 4.2) after the surgical procedure at two gait speeds (1.2m/s and 1.5m/s). The average weight loss was 26.7kg (SD 9.2kg), corresponding to 21.5% (SD 6.8%) of the initial weight. We observed a decrease in step width at both gait speeds, but no changes in relative double support or swing time or stride length. A significant decrease was noted in the absolute values of peak knee abductor, peak knee flexor and peak hip extensor moments. However, the moment values normalized by the body weight and height remained unchanged in most cases. Thus, we conclude that weight loss reduces hip and knee joint moments in proportion to the amount of weight lost. PMID:22633006

  11. Response of sagittal plane gait kinematics to weight-supported treadmill training and functional neuromuscular stimulation following stroke.

    PubMed

    Daly, Janis J; Roenigk, Kristen L; Butler, Kristen M; Gansen, Jennifer L; Fredrickson, Eric; Marsolais, E Byron; Rogers, Jean; Ruff, Robert L

    2004-01-01

    After stroke, persistent gait deficits cause debilitating falls and poor functional mobility. Gait restoration can preclude these outcomes. Sixteen subjects (>12 months poststroke) were randomized to two gait training groups. Group 1 received 12 weeks of treatment, 4 times a week, 90 min per session, including 30 min strengthening and coordination, 30 min over-ground gait training, and 30 min weight-supported treadmill training. Group 2 received the same treatment, but also used functional neuromuscular stimulation (FNS) with intramuscular (IM) electrodes (FNS-IM) for each aspect of treatment. Outcome measures were kinematics of gait swing phase. Both groups showed no significant pre-/posttreatment gains in peak swing hip flexion. Group 1 (no FNS) had no significant gains in other gait components at posttreatment or at follow-up. Group 2 (FNS-IM) had significant gains in peak swing knee flexion and mid-swing ankle dorsiflexion (p < 0.05) that were maintained for 6 months. PMID:15685469

  12. The effect of backpack load on the gait of normal adolescent girls

    Microsoft Academic Search

    Daniel HK Chow; Monica LY Kwok; Alexander CK Au-Yang; Andrew D Holmes; Jack CY Cheng; Fiona YD Yao

    2005-01-01

    Concerns regarding the effects of load carriage have led to recommendations that backpacks be limited to 10?–?15% of body weight, based on significant changes in physical performance. However, gait responses to backpack loads are not entirely consistent and there is a particular lack of data regarding load-bearing gait in adolescent females. Gait patterns of 22 normal adolescent girls were recorded

  13. Weight-bearing MRI of patellofemoral joint cartilage contact area

    Microsoft Academic Search

    Garry E. Gold; Thor F. Besier; Christine E. Draper; Deanna S. Asakawa; Scott L. Delp; Gary S. Beaupre

    2004-01-01

    Purpose: To measure contact area of cartilage in the patel- lofemoral joint during weight bearing using an open MRI scanner. Materials and Methods: We developed an MR-compatible back support that allows three-dimensional imaging of the patellofemoral cartilage under physiologic weight-bearing conditions with negligible motion artifact in an open MRI scanner. To measure contact areas, we trained observers us- ing a

  14. Improvement of gait ability with a short-term intensive gait rehabilitation program using body weight support treadmill training in community dwelling chronic poststroke survivors

    PubMed Central

    Takao, Toshifumi; Tanaka, Naoki; Iizuka, Noboru; Saitou, Hideyuki; Tamaoka, Akira; Yanagi, Hisako

    2015-01-01

    [Purpose] Most previous studies have shown that body weight support treadmill training (BWSTT) can improve gait speed poststroke patients. The purpose of this study was to evaluate effectiveness of a short-term intensive program using BWSTT among community dwelling poststroke survivors. [Subjects] Eighteen subjects participated in this study. The treatment group was composed of 10 subjects (2 women; 8 men; mean age, 59.1 ± 12.5?years; time since stroke onset, 35.3 ± 33.2 months), whereas the control group was made up of 8 subjects (3 women; 5 men; mean age, 59.8 ± 6.3?years; time since stroke onset, 39.3 ± 27.3 months). [Methods] The treatment group received BWSTT 3 times a week for 4 weeks (a total of 12 times), with each session lasting 20 minutes. The main outcome measures were maximum gait speed on a flat floor, cadence, and step length. [Results] No differences were observed in the baseline clinical data between the 2 groups. The gait speed in the treatment group was significantly improved compared with that in the control by 2-way ANOVA, while the other parameters showed no significant interaction. [Conclusion] These results suggested that short-term intensive gait rehabilitation using BWSTT was useful for improving gait ability among community dwelling poststroke subjects. PMID:25642063

  15. Weights and hematology of wild black bears during hibernation

    USGS Publications Warehouse

    DelGiudice, Glenn D.; Rogers, Lynn L.; Allen, Arthur W.; Seal, U.S.

    1991-01-01

    We compared weights and hematological profiles of adult (greater than 3-yr-old) female black bears (Ursus americanus) during hibernation (after 8 January). We handled 28 bears one to four times (total of 47) over 4 yr of varying mast and berry production. Mean weight of lactating bears was greater (P less than 0.0001) than that of non-lactating females. White blood cells (P less than 0.05) and mean corpuscular volume (P = 0.005) also differed between lactating and non-lactating bears. Hemoglobin (P = 0.006) and mean corpuscular hemoglobin concentration (P = 0.02) varied among years; values were lowest during 1975, following decreased precipitation and the occurrence of a second year of mast and berry crop shortages in a three-year period. Significant (P less than 0.05) interaction between reproductive status (lactating versus non-lactating) and study year for hemoglobin, red blood cells, and packed cell volume, and increased mean corpuscular volume, suggested a greater nutritional challenge for lactating females compared to non-lactating females during the 1975 denning season. Our data suggest that hematological characteristics of denning bears may be more sensitive than weights as indicators of annual changes in nutritional status; however, other influential factors, in addition to mast and berry crop production, remain to be examined.

  16. Effects of backpack weight on posture, gait patterns and ground reaction forces of male children with obesity during stair descent.

    PubMed

    Song, Qipeng; Yu, Bing; Zhang, Cui; Sun, Wei; Mao, Dewei

    2014-01-01

    This study investigates the effects of backpack weight on posture, gait pattern, and ground reaction forces for children with obesity in an attempt to define a safe backpack weight limit for them. A total of 16 obese (11.19 ± 0.66 years of age) and 21 normal body weight (11.13 ± 0.69 years of age) schoolboys were recruited. Two force plates and two video cameras were used. Multivariate analysis of variance with repeated measures was employed. Obese children showed increased trunk and head forward inclination angle, gait cycle duration and stance phase, decreased swing phase, and increased ground reaction force in the medial-lateral and anterior-posterior directions when compared with male children with a normal body weight. The changes were observed even with an empty backpack in comparison with normal body weight children and a 15% increase in backpack weight led to further instability and damage on their already strained bodies. PMID:24650337

  17. The effect of load carriage on the gait of girls with adolescent idiopathic scoliosis and normal controls

    Microsoft Academic Search

    Daniel H. K. Chow; Monica L. Y. Kwok; Alexander C. K. Au-Yang; Andrew D. Holmes; Jack C. Y. Cheng; Fiona Y. D. Yao; M. S. Wong

    2006-01-01

    Adolescent idiopathic scoliosis (AIS) and load-bearing both appear to place similar demands on gait, but no data regarding the combined effects of load-bearing gait in subjects with AIS could be found.The gait patterns of 22 normal adolescent girls and 28 girls with mild AIS (Cobb angle<25°) were recorded at backpack loads of 0, 7.5, 10, 12.5 and 15% body weight.

  18. Using Gait as a Biometric, via Phase-weighted Magnitude Spectra

    Microsoft Academic Search

    David Cunado; Mark S. Nixon; John N. Carter

    1997-01-01

    Abstract. Gait is a ,biometric which ,is subject ,to increasing ,interest. Current approaches,include modelling ,gait as a ,spatio-temporal sequence ,and ,as an articulated model. By considering legs only, gait can be considered to be the motion,of interlinked pendula. We describe how,the Hough transform is used to extract the lines which represent legs in sequences,of video,images. The change in inclination of

  19. A randomised controlled clinical trial and gait analysis of fixed- and mobile-bearing total knee replacements with a five-year follow-up.

    PubMed

    Jolles, B M; Grzesiak, A; Eudier, A; Dejnabadi, H; Voracek, C; Pichonnaz, C; Aminian, K; Martin, E

    2012-05-01

    This study compared the outcome of total knee replacement (TKR) in adult patients with fixed- and mobile-bearing prostheses during the first post-operative year and at five years' follow-up, using gait parameters as a new objective measure. This double-blind randomised controlled clinical trial included 55 patients with mobile-bearing (n = 26) and fixed-bearing (n = 29) prostheses of the same design, evaluated pre-operatively and post-operatively at six weeks, three months, six months, one year and five years. Each participant undertook two walking trials of 30 m and completed the EuroQol questionnaire, Western Ontario and McMaster Universities osteoarthritis index, Knee Society score, and visual analogue scales for pain and stiffness. Gait analysis was performed using five miniature angular rate sensors mounted on the trunk (sacrum), each thigh and calf. The study population was divided into two groups according to age (? 70 years versus > 70 years). Improvements in most gait parameters at five years' follow-up were greater for fixed-bearing TKRs in older patients (> 70 years), and greater for mobile-bearing TKRs in younger patients (? 70 years). These findings should be confirmed by an extended age controlled study, as the ideal choice of prosthesis might depend on the age of the patient at the time of surgery. PMID:22529085

  20. Patellofemoral joint contact area increases with knee flexion and weight-bearing

    E-print Network

    Stanford University

    subjects to be scanned without motion artifact in both weight-bearing (0.45 body weight per leg) and reduced loading con- ditions (ÔunloadedÕ at 0.15 body weight) at each knee flexion posture. Male subjects

  1. Changes in skeletal muscle gene expression consequent to altered weight bearing

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Kirby, C. R.

    1992-01-01

    Skeletal muscle is a dynamic organ that adapts to alterations in weight bearing. This brief review examines changes in muscle gene expression resulting from the removal of weight bearing by hindlimb suspension and from increased weight bearing due to eccentric exercise. Acute (less than or equal to 2 days) non-weight bearing of adult rat soleus muscle alters only the translational control of muscle gene expression, while chronic (greater than or equal to 7 days) removal of weight bearing appears to influence pretranslational, translational, and posttranslational mechanisms of control. Acute and chronic eccentric exercise are associated with alterations of translational and posttranslational control, while chronic eccentric training also alters the pretranslational control of muscle gene expression. Thus alterations in weight bearing influence multiple sites of gene regulation.

  2. Influence of Hindlimb Unweighting and Intermittent Weight Bearing on Dynamics of Nuclei in Rat Soleus Muscle

    PubMed Central

    2003-01-01

    The purpose of this study was to examine differences in the inhibitory effect of disuse atrophy as a result of intermittent weight bearing in terms of the dynamics of nuclei in rat soleus muscle. Disuse muscle atrophy was induced by hindlimb suspension for two weeks. Forty-nine male Wistar rats (body weight: 190–228 g) were divided into the control group (CON) and the experimental group. The experimental group was subdivided into four groups: hindlimb suspension alone (HS), weight bearing for 10 minutes × 4 times/day (W10), weight bearing for 20 minutes × 2 times/day (W20), and weight bearing for 40 minutes × one time/day (W40). In addition to histochemical examination, this study examined both cell proliferation and apoptosis in terms of the dynamics of myonuclei immuno-histochemically. The mean cross-sectional area of muscle fibers demonstrated the effect of weight bearing. The number of proliferating myonuclei per 100 muscle fibers was decreased in the experimental groups as compared with CON. Proliferating myonuclei in W10 and W40 were more than HS, indicating the effect of weight bearing. Apoptotic myonuclei was increased in the experimental groups as compared with CON. This parameter in W10 and W40 were statistically not significantly different from CON, suggesting that these weight bearing methods can prevent the loss of myonuclei by apoptosis. However, W20 was not significantly different from HS in terms of the dynamics of myonuclei. This suggests that weight bearing for W20 was ineffective. The results in this study indicated the possibility of inducing different effects by the frequency of weight bearing. PMID:25792927

  3. Adaptive body weight support controls human activity during robot-aided gait training

    Microsoft Academic Search

    Alexander Duschau-Wicke; Simon Felsenstein; Robert Riener

    2009-01-01

    Current clinical practice of robot-aided gait training is not as effective as expected. Cooperative control strategies aim at improving the effectiveness of robot-aided training by empowering patients to participate more actively. Our group has recently proposed the concept of bio-cooperative control, which explicitely considers the role of the human in the loop, as an extension of these strategies. A supervising

  4. Development of an advanced mechanised gait trainer, controlling movement of the centre of mass, for restoring gait in non-ambulant subjects.

    PubMed

    Hesse, S; Sarkodie-Gyan, T; Uhlenbrock, D

    1999-01-01

    The study aimed at further development of a mechanised gait trainer which would allow non-ambulant people to practice a gait-like motion repeatedly. To simulate normal gait, discrete stance and swing phases, lasting 60% and 40% of the gait cycle respectively, and the control of the movement of the centre of mass were required. A complex gear system provided the gait-like movement of two foot plates with a ratio of 60% to 40% between the stance and swing phases. A controlled propulsion system adjusted its output according to patient's efforts. Two eccenters on the central gear controlled phase-adjusted the vertical and horizontal position of the centre of mass. The patterns of sagittal lower limb joint kinematics and of muscle activation of a normal subject were similar when using the mechanised trainer and when walking on a treadmill. A non-ambulatory hemiparetic subject required little help from one therapist on the gait trainer, while two therapists supported treadmill walking. Gait movements on the trainer were highly symmetrical, impact-free, and less spastic. The weight-bearing muscles were activated in a similar fashion during both conditions. The vertical displacement of the centre of mass was bi-instead of mono-phasic during each gait cycle on the new device. In conclusion, the gait trainer allowed wheelchair-bound subjects the repetitive practice of a gait-like movement without overstraining therapists. PMID:10472726

  5. Change of weight-bearing pattern before and after plantar reconstruction with free anterolateral thigh flap.

    PubMed

    Sekido, Mitsuru; Yamamoto, Yuhei; Furukawa, Hiroshi; Sugihara, Tsuneki

    2004-01-01

    We reconstructed a large-sized defect at the weight-bearing plantar region by a free anterolateral thigh flap successfully. This is the first case report of using the anterolateral thigh flap for reconstruction of the plantar foot. Based on the preoperative and postoperative pedogram examinations, the pressure distribution on the weight-bearing area reconstructed by the transferred flap was obviously improved and demonstrated a nearly normal pattern. No previous report has compared the weight-bearing pattern before and after large plantar reconstruction with a free flap. The anterolateral thigh free flap, which provides adequate bulk and contour of the foot, and which withstands weight pressure and shearing force and has the ability to provide recovery of sensation, is considered a good alternative in covering a large weight-bearing plantar defect. PMID:15274185

  6. A weighted multi-scale morphological gradient filter for rolling element bearing fault detection

    Microsoft Academic Search

    Bing Li; Pei-lin Zhang; Zheng-jun Wang; Shuang-shan Mi; Dong-sheng Liu

    2011-01-01

    This paper presents a novel signal processing scheme, named the weighted multi-scale morphological gradient filter (WMMG), for rolling element bearing fault detection. The WMMG can depress the noise at large scale and preserve the impulsive shape details at small scale. Both a simulated signal and vibration signals from a bearing test rig are employed to evaluate the performance of the

  7. Variation in human gait intervals on a treadmill 

    E-print Network

    Abrams, Mark Alan

    1994-01-01

    Analysis This study investigated normal human gait on a treadmill by measuring the time between successive mid-swings, that is the point in the gait cycle in which one leg swings past the stance (weight bearing) leg. Instrumentation detected which leg... for interval marking was the mid-swing event. The mid-swing is the state in which the swinging leg passes the stance leg. The system measured time intervals between successive mid- swings with the use of a reflective sensor. Foot switches have been used...

  8. Body weight support by virtual model control of an impedance controlled exoskeleton (LOPES) for gait training.

    PubMed

    van der Kooij, Herman; Koopman, Bram; van Asseldonk, Edwin H F

    2008-01-01

    The feasibility of an alternative method to support body weight in a powered exoskeleton is demonstrated. Instead of using an overhead suspension system, body weight is supported by augmenting the joint moments through virtual model control. The advantages of this novel method is that it allows for independent support of the left and right leg, and does not interfere with the excitation of cutanous afferents and balance of the body or trunk. Results show that after a short familiarization period the activity of muscles during initial stance reduces and kinematics become close to normal. PMID:19163077

  9. Osteoporosis Knowledge, Calcium Intake, and Weight-Bearing Physical Activity in Three Age Groups of Women.

    ERIC Educational Resources Information Center

    Terrio, Kate; Auld, Garry W.

    2002-01-01

    Determined the extent and integration of osteoporosis knowledge in three age groups of women, comparing knowledge to calcium intake and weight bearing physical activity (WBPA). Overall calcium intake was relatively high. There were no differences in knowledge, calcium intake, or WBPA by age, nor did knowledge predict calcium intake and WBPA. None…

  10. Patellofemoral joint contact area increases with knee flexion and weight-bearing

    Microsoft Academic Search

    Thor F. Besier; Christine E. Draper; Garry E. Gold; Gary S. Beauprea; Scott L. Delp

    2005-01-01

    Patellofemoral pain is a common and debilitating disorder. Elevated cartilage stress of the patellofemoral joint is hypothesized to play a role in the onset of pain. Estimating cartilage stress requires accurate measurements of contact area. The purpose of this study was to estimate patellofemoral joint contact areas in a group of healthy, pain-free subjects during upright, weight-bearing conditions. Sixteen subjects

  11. A Proof of Concept for a Wireless Ambulatory Weight Bearing Measurement System in Rehabilitation and Telerehabilitation Applications

    Microsoft Academic Search

    Ariane Authier; Patrick Boissy; Jacques Beauvais; Réjean Fontaine

    2007-01-01

    Weight bearing is an important clinical variable for rehabilitation specialists. The objectives of this proof of concept study were to design and build a wireless system for weight bearing measurement that would provide accurate dynamic and static measurements of plantar forces from multiple sites. The proposed system consists of two shoes instrumented with miniature load cells connected to ankle modules

  12. The influence of gastrocnemius stretching combined with joint mobilization on weight-bearing ankle dorsiflexion passive range of motion

    PubMed Central

    Kang, Min-Hyeok; Lee, Dong-Kyu; Kim, Soo-Yong; Kim, Jun-Seok; Oh, Jae-Seop

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effect of gastrocnemius stretching combined with talocrural joint mobilization on weight-bearing ankle dorsiflexion passive range of motion. [Subjects] Eleven male subjects with bilateral limited ankle dorsiflexion passive range of motion with knee extended participated in this study. [Methods] All subjects received talocrural joint mobilization while performing gastrocnemius stretching. Ankle dorsiflexion passive range of motion was measured using an inclinometer under weight-bearing conditions before and immediately after intervention. A paired t-test was used to analyze the difference between weight-bearing ankle dorsiflexion passive range of motion pre- and post-intervention. [Results] A significant increase in weight-bearing ankle dorsiflexion passive range of motion was found post-intervention compared with pre-intervention. [Conclusion] These findings demonstrate that gastrocnemius stretching combined with joint mobilization is effective for increasing weight-bearing ankle dorsiflexion passive range of motion.

  13. The energy expenditure of non-weight bearing crutch walking on the level and ascending stairs.

    PubMed

    Moran, Jonathan; Murphy, Alexandra; Murphy, David; Austin, Andy; Moran, Danielle; Cronin, Caitriona; Guinan, Emer; Hussey, Juliette

    2015-06-01

    Crutches are commonly prescribed to patients with lower limb dysfunction during rehabilitation to assist with mobility. The aim of this study was to determine the energy expenditure for non-weight bearing crutch walking on level ground and ascending stairs at a self selected speed in a healthy adult population. Thirty-one healthy male and female adults (mean±SD: age 21.6±1.2 years; height 170.8±10.8cm; weight 70.8±11.4kg) mobilised non-weight bearing with elbow crutches along a 30m corridor and (with one crutch) up a flight of 13 stairs. Energy expenditure for each activity was measured by indirect calorimetry using the COSMED K4b(2) portable ergospirometry system. The established VO2 values were 16.4ml/kg/min for crutch walking on level ground and 17.85ml/kg/min for stair climbing. Non-weight bearing crutch walking at a self selected speed on the level ground and up a flight of stairs resulted in a MET value of 4.57 and 5.06 respectively. The mean heart rate (HR) for crutch walking along the flat was 117.06±20.54beats per minute (bpm), while the mean HR for ambulating upstairs with crutches was 113.91±19.32bpm. The increased energy demands of non-weight bearing crutch walking should be considered by physical therapists when instructing patients on crutch use. Further investigation to determine the implications of these results in populations with chronic disease is warranted. PMID:25891530

  14. The impact of adding weight-bearing exercise versus nonweight bearing programs to the medical treatment of elderly patients with osteoporosis

    PubMed Central

    Shanb, Alsayed A.; Youssef, Enas F.

    2014-01-01

    Background: Osteoporosis is a major public health problem affecting the elderly population, particularly women. The objective of the study was to evaluate the effects of adding weight-bearing exercise as opposed to nonweight-bearing programs to the medical treatment of bone mineral density (BMD) and health-related quality of life (HRQoL) of elderly patients with osteoporosis. Materials and Methods: Participating in the study were 40 elderly osteoporotic patients (27 females and 13 males), with ages ranging from 60 to 67 years, who were receiving medical treatment for osteoporosis. They were assigned randomly into two groups: Group-I: Twenty patients practiced weight-bearing exercises. Group-II: Twenty patients did nonweight-bearing exercises. All patients trained for 45-60 min/session, two sessions/week for 6 months. BMD of the lumbar spine, right neck of femur, and right distal radial head of all patients were measured by dual-energy X-ray absorptiometry before and after both treatment programs. In addition, the QoL was measured by means of the HRQoL “ECOS-16” questionnaire. Results: T-tests proved that mean values of BMD of the lumbar spine, right neck of femur and right distal radial head were significantly increased in both groups with greater improvement in the weight-bearing group. The QoL was significantly improved in both groups, but the difference between them was not significant. Conclusion: Addition of weight-bearing exercise program to medical treatment increases BMD more than nonweight-bearing exercise in elderly subjects with osteoporosis. Furthermore, both weight-bearing and nonweight-bearing exercise programs significantly improved the QoL of patients with osteoporosis. PMID:25374469

  15. Recovery of lower limb function following 6 weeks of non-weight bearing

    NASA Astrophysics Data System (ADS)

    MacIntyre, Donna L.; Eng, Janice J.; Allen, Trevor J.

    2005-05-01

    Skeletal muscle weakness and atrophy occur following an extended period of decreased use, including space flight and limb unloading. It is also likely that affected muscles will be susceptible to a re-loading injury when they begin return to earth or weight bearing. However, there is a paucity of literature evaluating the response of human unloaded muscle to exercise and return to activity. The purpose of this pilot study was to evaluate the soreness, function and strength response of muscle to re-loading in seven patients who were non-weight bearing for 6 weeks, compared to five healthy subjects. Function improved significantly over time for the patients but was still less than the healthy subjects over 12 weeks of physiotherapy. Concentric quadriceps muscle strength increased significantly over time for the patients. There was considerable variability in the patients' reports of muscle soreness but there were no significant changes over time or between groups.

  16. Weight bearing through flexed upper limbs in quadriplegics with paralyzed triceps brachii muscles

    Microsoft Academic Search

    LA Harvey; J Crosbie

    1999-01-01

    Study design: A biomechanical analysis of lifting through flexed and extended elbows in C5 and C6 quadriplegics. Objective: To determine the mechanisms used by C5 and C6 quadriplegics to prevent elbow collapse when bearing weight through flexed upper limbs. Setting: A biomechanics laboratory. Methods: Six motor complete C5 and C6 quadriplegic subjects with paralysis of their triceps brachii muscles were

  17. Surface texture and micromechanics of ultra high molecular weight polyethylene (UHMWPE) orthopaedic implant bearings

    Microsoft Academic Search

    Monica A. Schmidt

    2001-01-01

    Tibial bearings of ultra-high molecular weight polyethylene (UHMWPE) were characterized to identify differences in morphology, surface texture (roughness and skewness), and micro-scale mechanical behavior. These orthopaedic implant components were fabricated by direct molding or by machining after isostatic compression molding. Sterilization was by gamma irradiation (3.3 Mrad) in air, followed by shelf aging for 2 years. Comparisons were made between

  18. Functional Comparison of Immediate and Late Weight Bearing after Ankle Bimalleolar Fracture Surgery

    PubMed Central

    A??r, ?smail; Tunçer, Nejat; Küçükdurmaz, Fatih; Gümüsta?, Seyitali; Akgül, Esra Demirel; Akpinar, Fuat

    2015-01-01

    Aim : The aim of the study is to compare immediate weight bearing with below-knee cast or immobilization with plaster splint in 6 weeks in patients after operative treatment for ankle bimalleolar fractures. Methods : Fifty-three patients with ankle bimalleolar fractures were treated operatively in 2005 to 2010 and then were randomly allocated to two groups. Immediately weight bearing in a below-knee cast (26 patients) and immobilization in a plaster splint for the first six postoperative weeks (27 patients). A mean age 37.9 (min 17; max 72). An average follow-up 26.1 months. (min 14; max 55). All fractures were classified with Lauge-Hansen classification. Functional results of both groups were evaluated with AOFAS for the postoperative one year after surgical treatment. Results : According to the AOFAS scoring system, results were excellent and good in 17 patients in group 1. On the other hand, results were excellent and good in 14 patients in group 2. Conclusion : As a result we think that weight bearing protocol should be advantaged for patients with ankle bimalleolar fractures after surgical treatment immediately.

  19. Patellofemoral joint contact area increases with knee flexion and weight-bearing.

    PubMed

    Besier, Thor F; Draper, Christine E; Gold, Garry E; Beaupré, Gary S; Delp, Scott L

    2005-03-01

    Patellofemoral pain is a common and debilitating disorder. Elevated cartilage stress of the patellofemoral joint is hypothesized to play a role in the onset of pain. Estimating cartilage stress requires accurate measurements of contact area. The purpose of this study was to estimate patellofemoral joint contact areas in a group of healthy, pain-free subjects during upright, weight-bearing conditions. Sixteen subjects (8 female, 8 male) were scanned in a GE Signa SP open configuration MRI scanner, which allowed subjects to stand or squat while reclining 25 degrees from vertical with the knee positioned at 0 degrees , 30 degrees , or 60 degrees of flexion. A custom-built backrest enabled subjects to be scanned without motion artifact in both weight-bearing (0.45 body weight per leg) and reduced loading conditions ('unloaded' at 0.15 body weight) at each knee flexion posture. Male subjects displayed mean unloaded patellofemoral joint contact areas of 210, 414, and 520 mm(2) at 0 degrees , 30 degrees and 60 degrees of knee flexion, respectively. Female subjects' unloaded contact areas were similar at full extension (0 degrees ), but significantly smaller at 30 degrees and 60 degrees (p<0.01), with mean values of 269 and 396 mm(2), respectively. When normalized by patellar dimensions (heightxwidth), contact areas were not different between genders. Under weight-bearing conditions, contact areas increased by an average of 24% (p<0.05). This study highlights the differences in patellofemoral joint contact area between gender, knee flexion postures, and physiologic loading conditions. PMID:15734247

  20. A weighted multi-scale morphological gradient filter for rolling element bearing fault detection.

    PubMed

    Li, Bing; Zhang, Pei-lin; Wang, Zheng-jun; Mi, Shuang-shan; Liu, Dong-sheng

    2011-10-01

    This paper presents a novel signal processing scheme, named the weighted multi-scale morphological gradient filter (WMMG), for rolling element bearing fault detection. The WMMG can depress the noise at large scale and preserve the impulsive shape details at small scale. Both a simulated signal and vibration signals from a bearing test rig are employed to evaluate the performance of the proposed technique. The traditional envelope analysis and a multi-scale enveloping spectrogram algorithm combining continuous wavelet transform and envelope analysis (WT-EA) are also studied and compared with the presented WMMG. Experimental results have demonstrated the effectiveness of the WMMG to extract the impulsive components from the raw vibration signal with strong background noise. We also investigated the classification performance on identifying bearing faults based on the WMMG and statistical parameters with varied noise levels. Application results reveal that the WMMG achieves the same or better performance as EA and WT-EA. Meanwhile, the WMMG requires low computation cost and is very suitable for on-line condition monitoring of bearing operating states. PMID:21723552

  1. Weight-Bearing Exercise Accuracy Influences Muscle Activation Strategies of the Knee

    PubMed Central

    Madhavan, Sangeetha; Shields, Richard K.

    2014-01-01

    Purpose Dynamic stability of the knee joint is a research topic of increasing focus after ACL injury, stroke, and incomplete spinal cord injury. Since rehabilitation programs use functional weight-bearing tasks to improve neuromuscular control of the knee, it is important to understand the adaptability of muscle control strategies during weight-bearing exercise. The purpose of this study was to compare muscle activation patterns during a single leg squat (SLS) exercise performed before and after feedback-controlled training. Methods This was a cross-sectional comparative study. Fifteen young, healthy individuals performed the SLS exercise while tracking a sinusoidal target with flexion and extension of the knee. The SLS instrument provided bidirectional resistance that was normalized to body weight. Six trials of 10 repetitions of the SLSs were performed to quantify improved performance (learning). Electromyographic activity from five muscles that cross the knee was analyzed. Accuracy of performance was measured by calculating the error between the target and actual knee displacement. Results Reduction in error measurements verified that individuals increased the accuracy of performance in each trial and retained this improvement across trials (p < 0.05). Modulation in muscle activity as a result of learning was reflected mainly in the biceps femoris, rectus femoris, and vastus lateralis muscles. Conclusion Increased accuracy with the SLS exercise was accompanied by a decrease in coactivation of selected musculature around the knee. This study presents a novel approach to quantify the effect of performance on muscle synergistic activation patterns during weight-bearing exercise. Controlled strengthening, as defined in this study, emphasizes accuracy of performance in conjunction with principles of strength training and has implications to knee control. PMID:17419885

  2. The Development of a Porcine Model to Evaluate Wound Healing and Infection of Transcutaneous Osseointegrated Weight-Bearing Prostheses

    E-print Network

    Colbert, Kevin

    2013-05-31

    the efficacy of the transcutaneous osseointegrated option, a physiologically- similar, axially-loaded, weight bearing animal model was developed. Two pigs were fit with transcutaneous osseointegrated prostheses in a single-stage amputation and implantation...

  3. Electromyographic analysis of the gluteus medius in five weight-bearing exercises.

    PubMed

    Krause, David A; Jacobs, Rebecca S; Pilger, Katie E; Sather, Becky R; Sibunka, Seth P; Hollman, John H

    2009-12-01

    Weight-bearing exercises are frequently used to train and strengthen muscles of the hip. These exercises have been advocated in the rehabilitation of a variety of hip and knee dysfunctions. Limited evidence is available to describe the level of muscle activation occurring with specific weight-bearing exercises. The purpose of this study was to investigate the level of activation of the gluteus medius muscle as measured by electromyographic (EMG) signal amplitude in 5 weight-bearing exercises. Twenty healthy subjects aged 21 to 30 years participated in the study. The EMG surface electrodes were positioned over the muscle belly of the gluteus medius. Subjects performed 5 exercises that consisted of bilateral stance, single limb stance, single limb stance on both a firm surface and an Airex cushion, and single limb squat on a firm surface and an Airex cushion. Statistical differences (rho < 0.05) in gluteus medius EMG values were found between single limb stance as compared with double limb stance, and single limb squat as compared with single limb stance. Single limb stance places more demands on the gluteus medius than double limb stance, whereas single limb squats are more demanding than single limb stance. Although exercises performed on an Airex cushion produced greater EMG values as compared with a firm surface, the difference was not statistically significant. The results, however, suggest that if the goal is to increase the challenge to the gluteus medius, dynamic, single limb exercises performed on unstable surfaces, such as a balance cushion, may place greater demands on the gluteus medius than similar exercises performed on stable surfaces. PMID:19910807

  4. A Pilot Study of Randomized Clinical Controlled Trial of Gait Training in Subacute Stroke Patients With Partial Body-Weight Support Electromechanical Gait Trainer and Functional Electrical Stimulation Six-Month Follow-Up

    Microsoft Academic Search

    Maple F. W. Ng; Raymond K. Y. Tong; Leonard S. W. Li

    2010-01-01

    Background and Purpose—This study aimed to assess the effectiveness of gait training using an electromechanical gait trainer with or without functional electrical stimulation for people with subacute stroke. Methods—This was a nonblinded randomized controlled trial with a 6-month follow-up. Fifty-four subjects were recruited within 6 weeks after stroke onset and were randomly assigned to 1 of 3 gait intervention groups:

  5. Weight-Bearing Hip Rotation Range of Motion in Female Golfers

    PubMed Central

    Armstrong, Charles; Gribble, Phillip

    2010-01-01

    Background Many sports involve movements during which the lower extremity functions as a closed kinetic chain, requiring weight-bearing (WB) range of motion (ROM). Assessment of the capacity for internal and external rotation motion at the hip is typically performed with the individual in a prone, supine, or seated position. Such measurements represent ROM in a non-weight bearing (NWB) position, and, as a result, may not appropriately assess the capacity of the joint to meet the demands of the athlete's sport. To date, no research exists which documents WB hip ROM in golfers relative to the ROM demands of the golf swing or the symmetry of weight-bearing hip rotation ROM in female golfers. Objectives Weight-bearing hip rotation ROM was measured in female golfers and compared to the actual hip rotation ROM that occurred during a full golf swing. Methods Fifteen right-handed, female collegiate golfers participated in the study. The WB hip rotation ROM was measured during three different stance conditions and during full golf swings using a custom-built testing device. These actions were captured using a 3-D motion analysis system. Results The golfers WB ROM was symmetrical for external rotation and internal rotation, p = 0.648 and p = 0.078, respectively. During the backswing, the golfers used approximately 20-25% of their available WB right internal rotation, and 50-75% of their available WB left external rotation. For the downswing, the golfers used approximately 34-37% of their available WB right external rotation and 84-131% of their available WB left internal rotation. The golfers used significantly more external and internal hip rotation ROM on the left (lead) hip during both phases of the full golf swing (p < 0.001), demonstrating an asymmetrical movement pattern. Discussion In general, golfers did not exceed the measured WB ROM limits during the golf swing but did demonstrate decreased WB internal rotation on the lead hip. Conclusion Clinicians need to pay special attention to functional (WB) hip rotation ROM in female golfers in order to assess injury risk related to the rotational hip asymmetry present during the golf swing. PMID:21589662

  6. Bears, Bears, Bears!

    NSDL National Science Digital Library

    Ms.Beason

    2011-04-16

    What are some things you learned about bears? Use these websites to find out about bears: Parts of a Bear Polar Bears Real Story of the Three Bears The truth about bears Brown Bears Now fill in your chart! Bear Fact Sheet Listen to your teacher for further instruction on completing a book about bears! ...

  7. Orthotic devices and gait in polio patients.

    PubMed

    Genêt, F; Schnitzler, A; Mathieu, S; Autret, K; Théfenne, L; Dizien, O; Maldjian, A

    2010-02-01

    Polio survivors are aging and facing multiple pathologies. With age, walking becomes more difficult, partly due to locomotor deficits but also as a result of weight gain, osteoarticular degeneration, pain, cardiorespiratory problems or even post polio syndrome (PPS). These additional complications increase the risk of falls in this population where the risk of fractures is already quite high. The key joint is the knee. The muscles stabilizing this joint are often weak and patients develop compensatory gait strategies, which could be harmful to the locomotor system at medium or long term. Classically, knee recurvatum is used to lock the knee during weight bearing; however, if it exceeds 10 degrees , the knee becomes unstable and walking is unsafe. Thus, regular medical monitoring is necessary. Orthoses play an important role in the therapeutic care of polio survivors. The aim is usually to secure the knee, preventing excessive recurvatum while respecting the patient's own gait. Orthoses must be light and pressure-free if they are to be tolerated and therefore effective. Other joints present fewer problems and orthoses are rarely indicated just for them. The main issue lies in the prior evaluation of treatments' impact. Some deformities may be helpful for the patients' gait and, therefore, corrections may worsen their gait, especially if a realignment of segments is attempted. It is therefore essential to carefully pre-assess any change brought to the orthoses as well as proper indications for corrective surgery. In addition, it is essential for the patient to be monitored by a specialized team. PMID:20022835

  8. Effects of immobilization on rat hind limb muscles under non-weight-bearing conditions

    NASA Technical Reports Server (NTRS)

    Jaspers, Stephen R.; Fagan, Julie M.; Satarug, Soisungwan; Cook, Paul H.; Tischler, Marc E.

    1988-01-01

    The effect of stretched and unstretched immobilization of a hind limb on the concentration and the metabolism of proteins in the hind-limb muscles of rats was investigated. The animals were divided into three groups: (1) weight-bearing controls, (2) tail-cast-suspended, and (3) suspended, with one hind limb immobilized with the ankle in dorsiflexion (30-40 deg angle) and the other freely moving. It was found that unloading the hind limbs for 6 days by tail cast suspension caused soleus to atrophy and reduced growth of the gastrocnemius and plantaris muscles; unloading resulted in a higher degradation rate and lower synthesis rate in both in vitro and in vivo. Chronic stretch of the unloaded soleus not only prevented its atrophy but led to significant hypertrophy, relative to weight-bearing controls, with increases in both the sarcoplasmic and myofibrillar protein fractions. Immobilizing one ankle in dorsiflexion prevented the inhibition of growth in the plantaris and gastrocnemius muscles due to unloading.

  9. A Canine Non-Weight-Bearing Model with Radial Neurectomy for Rotator Cuff Repair

    PubMed Central

    Ji, Xiaoxi; Bao, Nirong; An, Kai-Nan; Amadio, Peter C.; Steinmann, Scott P.; Zhao, Chunfeng

    2015-01-01

    Background The major concern of using a large animal model to study rotator cuff repair is the high rate of repair retears. The purpose of this study was to test a non-weight-bearing (NWB) canine model for rotator cuff repair research. Methods First, in the in vitro study, 18 shoulders were randomized to 3 groups. 1) Full-width transections repaired with modified Mason-Allen sutures using 3-0 polyglactin suture, 2) Group 1 repaired using number 2 (#2) polyester braid and long-chain polyethylene suture, and 3) Partial-width transections leaving the superior 2 mm infraspinatus tendon intact without repair. In the in vivo study of 6 dogs, the infraspinatus tendon was partially transected as the same as the in vitro group 3. A radial neurectomy was performed to prevent weight bearing. The operated limb was slung in a custom-made jacket for 6 weeks. Results In the in vitro study, mean ultimate tensile load and stiffness in Group 2 were significantly higher than Group 1 and 3 (p<0.05). In the in vivo study, gross inspection and histology showed that the preserved superior 2-mm portion of the infraspinatus tendon remained intact with normal structure. Conclusions Based on the biomechanical and histological findings, this canine NWB model may be an appropriate and useful model for studies of rotator cuff repair. PMID:26107616

  10. Effects of feedback on activation of the quadriceps during weight-bearing tasks of the Wii

    PubMed Central

    Fernandes da Silva, Fabiano; Aparecido de Souza, Renato; Dias, Eric Fernandes; Silveira, Landulfo; Villaverde, Antonio Balbin

    2015-01-01

    [Purpose] This investigation evaluated the effect of real-time feedback on electrical activation of the quadriceps during 3 weight-bearing tasks of the Wii Fit Plus®. [Subjects] Thirty male healthy volunteers were recruited. [Methods] Activation of the vastus medialis, vastus lateralis, and rectus femoris muscles was recorded during virtual lunge, single leg extension, and single leg reach exercises. Each exercise was performed twice in 3 randomized experimental conditions (with visual feedback, with auditory feedback, and with no feedback). The normalized electromyographic data (using maximum voluntary isometric contraction) were analyzed using repeated measures analysis of variance and Tukey’s test. [Results] No significant difference was found in the muscles among the feedback conditions during the 3 exercises. However, the variation in the muscle activity of the vastus medialis and vastus lateralis (18.23–29.20% of maximum voluntary isometric contraction) was higher (47–62%) than that in the rectus femoris (7.35–12.98% of maximum voluntary isometric contraction). [Conclusion] Real-time feedback did not alter quadriceps activation during the Wii tasks. Additionally, these games showed electromyographic activation levels similar to those for the same tasks outside the virtual environment. The Wii weight-bearing tasks could therefore constitute a physical activity program but without the additional benefit of feedback. PMID:26180301

  11. Studies on the Cachexia of Tumor-bearing Animals I. Body Weight Changes, Carcass Composition, and Metabolic Studies

    Microsoft Academic Search

    MILOSLAV RECHCIGL; FLORA GRANTHAM; ROBERT E. GREENFIELD

    SUMMARY During the period of most rapid tumor growth, rats bearing Lymphosarcoma R2788 gained more weight than did control animals, although their food consumption was almost identical. Carcass and tumor analyses showed that there was an increased percentage of water in the tumor and the carcass when compared with normal con trols, sufficient to explain the increased weight gain. An

  12. Validation of a standardised gait score to predict the healing of tibial fractures.

    PubMed

    Macri, F; Marques, L F; Backer, R C; Santos, M J; Belangero, W D

    2012-04-01

    There is no absolute method of evaluating healing of a fracture of the tibial shaft. In this study we sought to validate a new clinical method based on the systematic observation of gait, first by assessing the degree of agreement between three independent observers regarding the gait score for a given patient, and secondly by determining how such a score might predict healing of a fracture. We used a method of evaluating gait to assess 33 patients (29 men and four women, with a mean age of 29 years (15 to 62)) who had sustained an isolated fracture of the tibial shaft and had been treated with a locked intramedullary nail. There were 15 closed and 18 open fractures (three Gustilo and Anderson grade I, seven grade II, seven grade IIIA and one grade IIIB). Assessment was carried out three and six months post-operatively using videos taken with a digital camera. Gait was graded on a scale ranging from 1 (extreme difficulty) to 4 (normal gait). Bivariate analysis included analysis of variance to determine whether the gait score statistically correlated with previously validated and standardised scores of clinical status and radiological evidence of union. An association was found between the pattern of gait and all the other variables. Improvement in gait was associated with the absence of pain on weight-bearing, reduced tenderness over the fracture, a higher Radiographic Union Scale in Tibial Fractures score, and improved functional status, measured using the Brazilian version of the Short Musculoskeletal Function Assessment questionnaire (all p < 0.001). Although further study is needed, the analysis of gait in this way may prove to be a useful clinical tool. PMID:22434473

  13. Gait disorders.

    PubMed

    Jankovic, Joseph

    2015-02-01

    Gait disorders are frequently accompanied by loss of balance and falls, and are a common cause of disability, particularly among the elderly. In many cases the cause is multifactorial, involving both neurologic and nonneurologic systems. Physical therapy and training, coupled with pharmacologic and surgical therapy, can usually provide some improvement in ambulation, which translates into better quality of life. More research is needed on the mechanisms of gait and its disorders as well as on symptomatic therapies. Better understanding of the pathophysiology of gait disorders should lead to more specific, pathogenesis-targeted therapies. PMID:25432732

  14. Improved Gait Recognition by Gait Dynamics Normalization

    E-print Network

    Sarkar, Sudeep

    gait stance are computed in the linear discriminant analysis space so as to maximize the discriminationImproved Gait Recognition by Gait Dynamics Normalization Zongyi Liu and Sudeep Sarkar, Senior Member, IEEE Abstract--Potential sources for gait biometrics can be seen to derive from two aspects: gait

  15. Quantitative Alterations in the Function of Bone Forming Cells Due to Reduced Weight Bearing

    NASA Technical Reports Server (NTRS)

    Doty, S. B.

    1985-01-01

    Rats subjected to spaceflight or suspended in a non-weight bearing position for 2 to 3 weeks, show a significant reduction in new bone formation. This reduction is associated with a decrease in akaline phosphatase activity in the differentiated osteoblast population. Those cells in the siaphyseal region of bone are more affected than the same cell type in metaphyseal bone. Measurements of alkaline phosphate activity in specific regions of bone, and the autoradiographic localization of H(3) proline in bone forming areas are described. Concomitant with decreased bone matrix synthesis, the osteoblast population also demonstrate changes in the Golgi/lysosomal complex as a result of whole animal suspension. Morphometric techniques are being applied for quantitation of the lysosomal population and the percentage of lysosomal or Golgi bodies containing acid phosphatase activity.

  16. Continuous Passive Motion, Early Weight Bearing, and Active Motion following Knee Articular Cartilage Repair

    PubMed Central

    Howard, Jennifer S.; Mattacola, Carl G.; Romine, Spencer E.; Lattermann, Christian

    2010-01-01

    Objective: To systematically review the literature regarding postoperative rehabilitation for articular cartilage repair: (1) does the use of continuous passive motion (CPM) enhance healing, and if so, what parameters should be applied? (2) Can active range of motion (AROM) be used in place of or with CPM? (3) When can individuals safely resume weight bearing (WB) following repair? Data Sources: A search using Medline, SportsDiscus, and CINAHL databases was performed with the following keywords: articular cartilage, AROM, CPM, microfracture, osteochondral allograft, autologous chondrocyte implantation, rehabilitation, weight bearing, and knee. Study Selection: Basic science or clinical outcomes examining the effects of CPM, AROM, or WB on knee articular cartilage healing. Data Extraction: Selected articles were rated using the Strength of Recommendation Taxonomy (SORT) to determine evidence for clinical application. Data Synthesis: Sixteen articles met selection criteria: 12 were basic science studies; 4 were clinical studies. Basic science evidence supporting CPM exists. However, few patient-oriented outcomes have been documented resulting in a SORT rating of C. Early WB and AROM received a SORT rating of B based on limited clinical research and patient-oriented outcomes. Conclusions: Basic science evidence supports CPM to maintain ROM, reduce pain, and promote healing. Patient-oriented research is needed to strengthen CPM’s recommendation. Limited evidence exists regarding early WB and AROM post cartilage repair. There is insufficient evidence to confidently address when to begin WB for maximum healing. Appropriate basic science and patient-oriented research are needed for rehabilitation protocols to maximize benefits of cartilage repair procedures.

  17. Comparison of dermatoscopic images of acral lentiginous melanoma and acral melanocytic nevus occurring on body weight-bearing areas

    PubMed Central

    Watanabe, Soko; Sawada, Mizuki; Ishizaki, Sumiko; Kobayashi, Ken; Tanaka, Masaru

    2014-01-01

    Background: Because body weight-bearing produces a shift in the horny layer, acral melanocytic nevus on the body weight-bearing area of the sole showed a regular fibrillar pattern (FP) due to slanting of the melanin columns in the horny layer. On the other hand, acral lentiginous melanoma (ALM) on the body weight-bearing area of the sole tended to show irregular fibrillar pattern showing rather structureless pigmentation instead of a parallel ridge pattern, which is due to the shift of the horny layer. Objective: To elucidate the subtle difference between the regular FP of nevus and irregular FP in ALM. Methods: In this study, the dermatoscopic features of five cases of ALM and five cases of acral melanocytic nevus on the weight-bearing area of the sole were compared. Results: All the cases with nevi showed regular FP showing regular distribution of fibrils, whereas all the melanomas showed irregular distribution of fibrils and colors. Fibrils in nevi tended to be clear at the furrows and dim at the ridges. White fibrils corresponding to the eccrine ducts in the horny layer were more often present on the ridges in ALM, which showed negative FP. Conclusion: Differentiating between the regular and irregular FP, including negative FP, might be helpful for the discrimination of melanoma from nevus. PMID:25396085

  18. Non-weight bearing-induced muscle weakness: the role of myosin quantity and quality in MHC type II fibers

    PubMed Central

    Kim, Jong-Hee

    2014-01-01

    We tested the hypothesis that non-weight bearing-induced muscle weakness (i.e., specific force) results from decreases in myosin protein quantity (i.e., myosin content per half-sarcomere and the ratio of myosin to actin) and quality (i.e., force per half-sarcomere and population of myosin heads in the strong-binding state during muscle contraction) in single myosin heavy chain (MHC) type II fibers. Fisher-344 rats were assigned to weight-bearing control (Con) or non-weight bearing (NWB). The NWB rats were hindlimb unloaded for 2 wk. Diameter, force, and MHC content were determined in permeabilized single fibers from the semimembranosus muscle. MHC isoform and the ratio of MHC to actin in each fiber were determined by gel electrophoresis and silver staining techniques. The structural distribution of myosin from spin-labeled fiber bundles during maximal isometric contraction was evaluated using electron paramagnetic resonance spectroscopy. Specific force (peak force per cross-sectional area) in MHC type IIB and IIXB fibers from NWB was significantly reduced by 38% and 18%, respectively. MHC content per half-sarcomere was significantly reduced by 21%. Two weeks of hindlimb unloading resulted in a reduced force per half-sarcomere of 52% and fraction of myosin strong-binding during contraction of 34%. The results suggest that reduced myosin and actin content (quantity) and myosin quality concomitantly contribute to non-weight bearing-related muscle weakness. PMID:24829495

  19. Early Weight Bearing of Calcaneal Fractures Treated by Intraoperative 3D-Fluoroscopy and Locked-Screw Plate Fixation

    PubMed Central

    Kienast, B; Gille, J; Queitsch, C; Kaiser, M.M; Thietje, R; Juergens, C; Schulz, A.P

    2009-01-01

    Operative therapy of intraarticular fractures of the calcaneus is an established surgical standard. The aim is an accurate reduction of the fracture with reconstruction of Boehler’s angle, length, axis and subtalar joint surface. Intraoperative 3D-fluoroscopy with the Siremobil Iso-C 3D® mobile C-arm system is a valuable assistant for accurate reconstruction of these anatomical structures. Remaining incongruities can be recognized and corrected intraoperatively. The achieved reduction can be fixed by the advantages of an internal fixator (locked-screw plate interface). In the period of October 2002 until April 2007 we operated 136 patients with intraarticular fractures of the calcaneus by means of anatomical reduction, and internal plate fixator under intraoperative control of 3D-fluoroscopy. All patients were supplied with an orthesis after the operation which allowed weight bearing of 10 kg for 12 weeks for the patients operated between October 2002 and October 2004 (Group A). Transient local osteoporosis was observed in all X-Rays at follow-up after an average of 8,6 months. Therefore we changed our postoperative treatment plan for the patients operated between November 2004 and April 2007 (Group B). Weight bearing started with 20 KG after 6 weeks, was increased to 40 KG after 8 weeks and full weight bearing was allowed after 10 weeks for these patients. In no case a secondary dislocation of the fracture was seen. No bone graft was used. At follow up the average American Foot and Ankle Society Score (AOFAS) were 81 for Group_A, compared to 84 for Group B, treated with earlier weight bearing. Autologous bone graft was not necessary even if weight bearing was started after a period of six weeks postoperatively. The combination of 3D-fluoroscopy with locked internal fixation showed promising results. If the rate of patients developing subtalar arthrosis will decrease by this management will have to be shown in long term follow up. PMID:19750017

  20. MR imaging of the forefoot under weight-bearing conditions: Position-related changes of the neurovascular bundles and the metatarsal heads in asymptomatic volunteers

    Microsoft Academic Search

    Dominik Weishaupt; Karl Treiber; Hilaire A. C. Jacob; Hans-Peter Kundert; Juerg Hodler; Borut Marincek; Marco Zanetti

    2002-01-01

    Purpose: To assess practicability of weight-bearing mag- netic resonance (MR) imaging of the forefoot, and to dem- onstrate position-related changes of the neurovascular bundles and the metatarsal heads in asymptomatic volun- teers. Materials and Methods: With an open-configuration MR system, 32 feet of 32 asymptomatic individuals aged 20-60 years were studied in supine and weight-bearing body po- sitions. Transverse T1-weighted

  1. Effects of removal of weight-bearing function on contractility and myosin isoform composition in single human skeletal muscle cells

    Microsoft Academic Search

    Lars Larsson; Xiaopeng Li; Hans E. Berg; Walter R. Frontera

    1996-01-01

    The purpose of this study was to investigate the effects of a 6-week period without weight bearing, achieved by bed rest,\\u000a on the contractile behaviour, myosin isoform expression and myofibrillar protein content of single human muscle fibres. Percutaneous\\u000a biopsied specimens of the quadriceps muscle were taken from three healthy male volunteers before and at the end of the experimental\\u000a period.

  2. Synergistic ablation does not affect atrophy or altered myosin heavy chain expression in the non-weight bearing soleus muscle

    NASA Technical Reports Server (NTRS)

    Linderman, J. K.; Talmadge, R. J.; Gosselink, K. L.; Tri, P. N.; Roy, R. R.; Grindeland, R. E.

    1996-01-01

    The purpose of this study was to investigate whether the soleus muscle undergoes atrophy and alterations in myosin heavy chain (MHC) composition during non-weight bearing in the absence of synergists. Thirty-two female rats were randomly assigned to four groups: control (C), synergistic ablation (ABL) of the gastrocnemius and plantaris muscles to overload the soleus muscle, hindlimb suspension (HLS), or a combination of synergistic ablation and hindlimb suspension (HLS-ABL). After 28 days of hindlimb suspension, soleus atrophy was more pronounced in HLS (58%) than in HLS-ABL (43%) rats. Compared to C rats, non-weight bearing decreased mixed and myofibrillar protein contents and Type I MHC 49%, 45%, and 7%, respectively, in HLS animals. In addition, de novo expression of fast Type IIx and Type IIb MHC (5% and 2%, respectively) was observed in HLS animals. Similarly, when compared to C rats, mixed and myofibrillar protein contents and Type I MHC decreased 43%, 46%, and 4%, respectively, in HLS-ABL animals. Also, de novo expression of Type IIx (4%) and IIb (1%) MHC was observed. Collectively, these data indicate that the loss of muscle protein and Type I MHC, and the de novo expression of Type IIx and Type IIb MHC in the rat soleus occur independently of the presence of synergists during non-weight bearing. Furthermore, these results confirm the contention that soleus mass and MHC expression are highly sensitive to alterations in mechanical load.

  3. Bilateral sleeve fractures of the patella in a 12-year-old boy with hereditary spastic paraparesis and crouch gait.

    PubMed

    Malone, Ailish; Kiernan, Damien; O Brien, Tim

    2013-01-01

    This is the first reported case of bilateral sleeve fractures of the patellae in a child with crouch gait. A 12-year-old boy with hereditary spastic paraparesis (HSP), who was found to have mid-stance crouch of 20° on previous gait analysis, presented with pain of gradual onset and limited mobility. There was no history of trauma. Three-dimensional gait analysis showed that extensor mechanism function during loading response was intact, but knee flexion in swing was significantly reduced, indicating protective guarding by rectus femoris. X-rays showed bilateral minimally displaced sleeve fractures of the patellae. These were treated with immobilisation in cylinder casts in extension for 4 weeks. Follow-up X-rays showed that the fractures had successfully united and the patient progressed to full weight bearing and mobility as tolerated. PMID:24306432

  4. Physiological responses and energy cost of walking on the Gait Trainer with and without body weight support in subacute stroke patients

    PubMed Central

    2014-01-01

    Background Robotic-assisted walking after stroke provides intensive task-oriented training. But, despite the growing diffusion of robotic devices little information is available about cardiorespiratory and metabolic responses during electromechanically-assisted repetitive walking exercise. Aim of the study was to determine whether use of an end-effector gait training (GT) machine with body weight support (BWS) would affect physiological responses and energy cost of walking (ECW) in subacute post-stroke hemiplegic patients. Methods Participants: six patients (patient group: PG) with hemiplegia due to stroke (age: 66?±?15y; time since stroke: 8?±?3 weeks; four men) and 6 healthy subjects as control group (CG: age, 76?±?7y; six men). Interventions: overground walking test (OWT) and GT-assisted walking with 0%, 30% and 50% BWS (GT-BWS0%, 30% and 50%). Main Outcome Measures: heart rate (HR), pulmonary ventilation, oxygen consumption, respiratory exchange ratio (RER) and ECW. Results Intervention conditions significantly affected parameter values in steady state (HR: p?=?0.005, V’E: p?=?0.001, V'O2: p?

  5. Biofeedback rehabilitation of posture and weight-bearing distribution in stroke: a center of foot pressure analysis

    PubMed Central

    De Nunzio, Alessandro Marco; Zucchella, Chiara; Spicciato, Francesca; Tortola, Paolo; Vecchione, Carmine; Pierelli, Francesco; Bartolo, Michelangelo

    2014-01-01

    Summary Weight bearing on the paretic lower extremity and transfer of weight from one lower extremity to the other are important goals of stroke rehabilitation. Improvements in these limb loading and weight transfer abilities have been shown to relate to improved performance of many functional activities. Unfortunately, valid and practical clinical measures of paretic lower extremity loading and weight transfer have not been identified. The purpose of this study was to quantitatively assess, through center of foot pressure (CoP) analysis of quiet upright stance control, recovery of paretic limb loading as a measure of weight transfer in early stroke subjects, testing the effectiveness of a targeted rehabilitation intervention based on audio-visual biofeedback. Thirty-seven adults with lower extremity motor impairment following unilateral, non-cerebellar stroke, were tested twice, at an interval of at least one month post stroke and following rehabilitation intervention aimed at correcting their asymmetrical weight bearing. The intervention was performed with (Study Group, SG) or without (Control Group, CG) a postural audio-visual biofeedback approach. Indices of postural stability and of balance control asymmetry were estimated by acquiring the movements of the CoP during quiet upright stance condition with or without visual input (eyes open, EO and eyes closed, EC). Clinical scales were also administered. Both the CG and the SG subjects showed improved control in upright stance posture as documented by significant improvements in the scale scores and indices of stability during both the EO and the EC condition. Only the SG showed a significantly reduced CoP index of asymmetry. The CoP index of asymmetry, correlating with clinical motor scales, is a valid measure of paretic limb loading during stroke recovery. Postural audio-visual biofeedback represented the more effective approach for reducing weight loading asymmetry of the lower limbs in stroke. PMID:25306123

  6. Study of the Polycarbonate-Urethane/Metal Contact in Different Positions during Gait Cycle

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Lobo-Escolar, Antonio

    2014-01-01

    Nowadays, a growing number of young and more active patients receive hip replacement. More strenuous activities in such patients involve higher friction and wear rates, with friction on the bearing surface being crucial to ensure arthroplasty survival in the long term. Over the last years, the polycarbonate-urethane has offered a feasible alternative to conventional bearings. A finite element model of a healthy hip joint was developed and adjusted to three gait phases (heel strike, mid-stance, and toe-off), serving as a benchmark for the assessment of the results of joint replacement model. Three equivalent models were made with the polycarbonate-urethane Tribofit system implanted, one for each of the three gait phases, after reproducing a virtual surgery over the respective healthy models. Standard body-weight loads were considered: 230% body-weight toe-off, 275% body-weight mid-stance, and 350% body-weight heel strike. Contact pressures were obtained for the different models. When comparing the results corresponding to the healthy model to polycarbonate-urethane joint, contact areas are similar and so contact pressures are within a narrower value range. In conclusion, polycarbonate-urethane characteristics are similar to those of the joint cartilage. So, it is a favorable alternative to traditional bearing surfaces in total hip arthroplasty, especially in young patients. PMID:25247180

  7. Study of the polycarbonate-urethane/metal contact in different positions during gait cycle.

    PubMed

    Gabarre, Sergio; Herrera, Antonio; Mateo, Jesús; Ibarz, Elena; Lobo-Escolar, Antonio; Gracia, Luis

    2014-01-01

    Nowadays, a growing number of young and more active patients receive hip replacement. More strenuous activities in such patients involve higher friction and wear rates, with friction on the bearing surface being crucial to ensure arthroplasty survival in the long term. Over the last years, the polycarbonate-urethane has offered a feasible alternative to conventional bearings. A finite element model of a healthy hip joint was developed and adjusted to three gait phases (heel strike, mid-stance, and toe-off), serving as a benchmark for the assessment of the results of joint replacement model. Three equivalent models were made with the polycarbonate-urethane Tribofit system implanted, one for each of the three gait phases, after reproducing a virtual surgery over the respective healthy models. Standard body-weight loads were considered: 230% body-weight toe-off, 275% body-weight mid-stance, and 350% body-weight heel strike. Contact pressures were obtained for the different models. When comparing the results corresponding to the healthy model to polycarbonate-urethane joint, contact areas are similar and so contact pressures are within a narrower value range. In conclusion, polycarbonate-urethane characteristics are similar to those of the joint cartilage. So, it is a favorable alternative to traditional bearing surfaces in total hip arthroplasty, especially in young patients. PMID:25247180

  8. Weight-Bearing and Mobilization in the Postoperative Care of Ankle Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Cohort Studies

    PubMed Central

    Smeeing, Diederik P. J.; Houwert, Roderick M.; Briet, Jan Paul; Kelder, Johannes C.; Segers, Michiel J. M.; Verleisdonk, Egbert Jan M. M.; Leenen, Luke P. H.; Hietbrink, Falco

    2015-01-01

    Purpose To determine the effectiveness and safety of interventions used for rehabilitation after open reduction and internal fixation of ankle fractures. Methods A systematic review and meta-analysis was performed using both randomized trials and cohort studies. The effect of mobilization, weight-bearing, and unprotected weight-bearing as tolerated on postoperative recovery was compared using the Olerud Molander score, return to work/daily activities, and the rate of complications. Results A total of 25 articles were included. Ankle exercises resulted in earlier return to work and/or daily activities compared to immobilization (mean difference (MD) -20.76 days; 95% confidence interval (CI) -40.02 to -1.50). There was no difference in the rate of complications between exercises and immobilization (risk ratio (RR) 1.22; 95% CI 0.60 to 2.45) or between early and late weight-bearing (RR 1.26; 95%CI 0.56 to 2.85). Interpretation Results of this meta-analysis show that following ankle surgery, 1) active exercises accelerate return to work and daily activities compared to immobilization, 2) early weight-bearing tends to accelerate return to work and daily activities compared to late weight-bearing. Active exercises in combination with immediate weight-bearing may be a safe option. PMID:25695796

  9. Muscle glucose uptake in the rat after suspension with single hindlimb weight bearing

    NASA Technical Reports Server (NTRS)

    Stump, Craig S.; Woodman, Christopher R.; Fregosi, Ralph F.; Tipton, Charles M.

    1993-01-01

    An examination is conducted of the effect of nonweight-bearing conditions, and the systemic influences of simulated microgravity on rat hindlimb muscles. The results obtained suggest that the increases in hindlimb muscle glucose uptake and extracellular space associated with simulated microgravity persist with hindlimb weightbearing, despite the prevention of muscle atrophy. The mechanism (or mechanisms) responsible for these effects are currently unknown.

  10. Weighting GPS Dual Frequency Observations: Bearing the Cross of Cross-Correlation

    Microsoft Academic Search

    Peter J. G. Teunissen; N. F. Jonkman; C. C. J. M. Tiberius

    1998-01-01

      A proper choice of the observation weight matrix is of importance for both adjusting and testing GPS data. Our understanding\\u000a of the noise characteristic of GPS observations, on which the weight matrix should be based, is, however, still underdeveloped.\\u000a This makes it difficult to draw up an appropriate weight matrix. The first and foremost purpose of this contribution is therefore

  11. Combined magnetic resonance imaging approach for the assessment of in vivo knee joint kinematics under full weight-bearing conditions.

    PubMed

    Al Hares, Ghaith; Eschweiler, Jörg; Radermacher, Klaus

    2015-06-01

    The development of detailed and specific knowledge on the biomechanical behavior of loaded knee structures has received increased attention in recent years. Stress magnetic resonance imaging techniques have been introduced in previous work to study knee kinematics under load conditions. Previous studies captured the knee movement either in atypical loading supine positions, or in upright positions with help of inclined supporting backrests being insufficient for movement capture under full-body weight-bearing conditions. In this work, we used a combined magnetic resonance imaging approach for measurement and assessment in knee kinematics under full-body weight-bearing in single legged stance. The proposed method is based on registration of high-resolution static magnetic resonance imaging data acquired in supine position with low-resolution data, quasi-static upright-magnetic resonance imaging data acquired in loaded positions for different degrees of knee flexion. The proposed method was applied for the measurement of tibiofemoral kinematics in 10 healthy volunteers. The combined magnetic resonance imaging approach allows the non-invasive measurement of knee kinematics in single legged stance and under physiological loading conditions. We believe that this method can provide enhanced understanding of the loaded knee kinematics. PMID:25979443

  12. Use of ultrahigh-molecular-weight polyethylene for bearing materials on a steel substrate

    Microsoft Academic Search

    V. N. Kornopol’tsev; D. M. Mognonov; I. A. Farion; V. E. Nikitin; V. A. Zakharov

    2009-01-01

    The paper presents results on the usage of ultrahigh-molecular-weight polyethylene for manufacture of antifrictional materials\\u000a on a steel substrate. Hot molding regimes are determined for the production of polymeric components. The optimum degree of\\u000a ultrahigh-molecular-weight polyethylene filling with graphite is determined (about 50 mass %) for the purpose of achieving\\u000a perfect triboengineering parameters of sheet antifrictional materials during operation against

  13. Effect of spaceflight on the non-weight-bearing bones of rat skeleton

    NASA Technical Reports Server (NTRS)

    Simmons, D. J.; Russell, J. E.; Winter, F.; Tran Van, P.; Vignery, A.; Baron, R.; Rosenberg, G. D.; Walker, W. V.

    1983-01-01

    The effects of weightlessness on the integrated growth and remodeling of nonweight-bearing bones (the mandibles, teeth, and ribs) were studied. Rats prelabeled with tetracycline to mark the surfaces of bone and tooth formation were subjected to spaceflight conditions for 18.5 days, followed by further injections of tetracycline on days 6 and 29 postflight.Results show that spaceflight conditions did not alter the rate of periosteal bone formation in the ribs and regions of the mandibles covered by masticatory muscles, although bone formation-calcification rates were found to be impaired at those sites in the jaw that had no contiguous muscle (molar region). The remodeling activity on the alveolar bone around the buccal roots of the molar teeth was found to be significantly reduced. While total Ca, P, and hydroxyproline concentrations in the jaws, incisors, and ribs were normal after spaceflight, it was determined that weightless conditions caused a delay in the maturation of bone mineral and matrix in the jaws. These anomalies were found to be corrected by 29 days postflight. These results indicate that most of the nonweight-bearing bones of the rat skeleton are at risk to the effects of weightlessness.

  14. Two Patients with Osteochondral Injury of the Weight-Bearing Portion of the Lateral Femoral Condyle Associated with Lateral Dislocation of the Patella

    PubMed Central

    Inoue, Hiroaki; Atsumi, Satoru; Ichimaru, Shohei; Fujiwara, Hiroyoshi; Kubo, Toshikazu

    2014-01-01

    Complications of patellar dislocation include osteochondral injury of the lateral femoral condyle and patella. Most cases of osteochondral injury occur in the anterior region, which is the non-weight-bearing portion of the lateral femoral condyle. We describe two patients with osteochondral injury of the weight-bearing surface of the lateral femoral condyle associated with lateral dislocation of the patella. The patients were 18- and 11-year-old females. Osteochondral injury occurred on the weight-bearing surface distal to the lateral femoral condyle. The presence of a free osteochondral fragment and osteochondral injury of the lateral femoral condyle was confirmed on MRI and reconstruction CT scan. Treatment consisted of osteochondral fragment fixation or microfracture, as well as patellar stabilization. Osteochondral injury was present in the weight-bearing portion of the lateral femoral condyle in both patients, suggesting that the injury was caused by friction between the patella and lateral femoral condyle when the patella was dislocated or reduced at about 90° flexion of the knee joint. These findings indicate that patellar dislocation may occur and osteochondral injury may extend to the weight-bearing portion of the femur even in deep flexion, when the patella is stabilized on the bones of the femoral groove. PMID:25506015

  15. Gait Analysis for Classification

    E-print Network

    Lee, Lily

    2003-06-26

    This thesis describes a representation of gait appearance for the purpose of person identification and classification. This gait representation is based on simple localized image features such as moments extracted from ...

  16. Gait analysis for classification

    E-print Network

    Lee, Lily, 1971-

    2002-01-01

    This thesis describes a representation of gait appearance for the purpose of person identification and classification. This gait representation is based on simple localized image features such as moments extracted from ...

  17. Biometric Gait Recognition Jeffrey E. Boyd1

    E-print Network

    Boyd, Jeffrey E.

    that affect both human and machine recognition of gaits, data used in gait and motion analysis, evaluation methods, existing gait and quasi gait recognition systems, and uses of gait analysis beyond biometric of gaits, data used in gait and motion analysis, evaluation methods, existing gait and quasi gait

  18. Planned Bone Resections Using an MRI-Based Custom Cutting Guide System Versus 3-Dimensional, Weight-Bearing Images in Total Knee Arthroplasty.

    PubMed

    Nam, Denis; Williams, Brandon; Hirsh, Jeffrey; Johnson, Staci R; Nunley, Ryan M; Barrack, Robert L

    2015-04-01

    Potential sources of alignment variability not yet investigated with the use of custom cutting guides (CCG) in total knee arthroplasty (TKA) are weight-bearing and lower extremity rotation. This study compared the preoperative planned bone resections created using an MRI-based CCG system to those from 3-dimensional, weight-bearing, full-length lower extremity images in 53 patients undergoing TKA. The angular difference between the proposed resections of the two systems was greater than 2° in 30.2% of patients for the distal femur, and 52.8% for the proximal tibia. An increased preoperative varus alignment had a slight association with an increased angular difference for the tibial resection (r=0.4). This study demonstrates weight-bearing and lower extremity rotation to be potential sources of alignment variability when using MRI-based CCGs. PMID:25533640

  19. Factored Interval Particle Filtering for Gait Analysis Jamal Saboune, Cedric Rose, and Francois Charpillet

    E-print Network

    Paris-Sud XI, Université de

    Factored Interval Particle Filtering for Gait Analysis Jamal Saboune, C´edric Rose, and Franc¸ois Charpillet Abstract-- Commercial gait analysis systems rely on wearable sensors. The goal of this study for efficiently weighting and resampling the particles. I. HUMAN MOTION CAPTURE Gait analysis is becoming a very

  20. A mechanized gait trainer for restoring gait in nonambulatory subjects

    Microsoft Academic Search

    Stefan Hesse; Dietmar Uhlenbrock; Cordula Werner; Anita Bardeleben

    2000-01-01

    Hesse S, Uhlenbrock D, Werner C, Bardeleben A. A mechanized gait trainer for restoring gait in nonambulatory subjects. Arch Phys Med Rehabil 2000;81:1158-61. Objective: To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. Device: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40%

  1. Gait characteristic analysis and identification based on the iPhone's accelerometer and gyrometer.

    PubMed

    Sun, Bing; Wang, Yang; Banda, Jacob

    2014-01-01

    Gait identification is a valuable approach to identify humans at a distance. In this paper, gait characteristics are analyzed based on an iPhone's accelerometer and gyrometer,and a new approach is proposed for gait identification. Specifically, gait datasets are collected by the triaxial accelerometer and gyrometer embedded in an iPhone. Then, the datasets are processed to extract gait characteristic parameters which include gait frequency, symmetry coefficient, dynamic range and similarity coefficient of characteristic curves. Finally, a weighted voting scheme dependent upon the gait characteristic parameters is proposed forgait identification. Four experiments are implemented to validate the proposed scheme. The attitude and acceleration solutions are verified by simulation. Then the gait characteristics are analyzed by comparing two sets of actual data, and the performance of the weighted voting identification scheme is verified by 40 datasets of 10 subjects. PMID:25222034

  2. Evaluation of a bisphosphonate enriched ultra-high molecular weight polyethylene for enhanced total joint replacement bearing surface functionality

    NASA Astrophysics Data System (ADS)

    Wright-Walker, Cassandra Jane

    Each year in the United States there is an increasing trend of patients receiving total joint replacement (TJR) procedures. Approximately a half million total knee replacements (TKRs) are performed annually in the United States with increasing prevalence attributed to baby-boomers, obesity, older, and younger patients. This trend is also seen for total hip replacements (THRs) as well. The use of ultra high molecular weight polyethylene (UHMWPE) inserts in TJRs results in wear particle-induced osteolysis, which is the predominant cause for prosthesis failure and revision surgery. Sub-micron size particle generation is inevitable despite the numerous efforts in improving this bearing material. Work by others has shown that the use of oral and intravenous systemic bisphosphonates (BP) can significantly minimize periprosthetic osteolysis. However, the systemic delivery and the high solubility of BPs results in a predominant portion of the drug being excreted via the kidney without reaching its target, bone. This doctoral research project is focused on the development and evaluation of a novel method to administer BPs locally using the inherent wear of UHMWPE for possible use as an anti-osteolysis treatment. For new materials to be considered, they must be mechanically and tribologically comparable to the current gold standard, UHMWPE. In order to evaluate this material, mechanical, drug elution and tribological experiments were performed to allow assessment of material properties. Tensile tests showed comparable yield stress and pin-on-disk testing showed comparable wear to standard virgin UHMWPE. Further, drug elution tests have shown that BP was released from the enriched material both in static and dynamic conditions. Additionally, an aggressive 2 million cycle total knee simulator experiment has shown statistically similar wear results for the two materials. Overall, this research has provided the groundwork for further characterization and development of a new potential material for total joint replacements as an enhancement to standard UHMWPE. This material shows significant potential as an alternative bearing material to indirectly increase TJR longevity by addressing osteolysis related issues.

  3. A palmar pressure sensor for measurement of upper limb weight bearing by the hands during transfers by paraplegics.

    PubMed

    Kunju, Nissan; Ojha, Rajdeep; Devasahayam, Suresh R

    2013-10-01

    Paraplegic patients have to effect transfer from one seat to another by using their upper limbs. In this process the hands bear almost the entire weight of the body in at least some phases of the transfer. It is desirable to train patients, especially those who are elderly and otherwise weak, to distribute their weight so as to avoid large forces being sustained on any one hand for an extended period. It is also desirable to evaluate the effectiveness of assistive devices like lower limb FES in sharing the load on the hand. This study presents a simple and versatile method of measuring palmar hand force during transfers by paraplegic patients. It is important that this force sensor should not interfere with the grasping and stabilizing properties of the hands and should permit normal transferring. The force sensor comprises an air-filled pouch or pillow that can be placed on any surface. This pneumatic sensor feels like upholstery padding on the surface on which it is placed. The sensor integrates the total pressure applied to the surface of the pouch, thereby obtaining the total force exerted by the palm/hand. The fabrication of the sensor is described, as well as the associated measurement circuit. The static calibration shows that the sensor is linear up to 350?N and the dynamic calibration shows that it has a bandwidth of 13?Hz. The sensor was fabricated using an inflated inelastic airbag attached to a pressure transducer. An automatic offset correction circuit in the preamplifier module ensures that any offset due to initial pressure or sensor drift is removed and the output is zero under no load condition. The key to this sensor arrangement is the ease of fitting it into the intended location without disturbing the existing arrangement for the subject's activities of daily living (ADL). PMID:23964668

  4. Phasic-to-tonic shift in trunk muscle activity relative to walking during low-impact weight bearing exercise

    NASA Astrophysics Data System (ADS)

    Caplan, Nick; Gibbon, Karl; Hibbs, Angela; Evetts, Simon; Debuse, Dorothée

    2014-11-01

    The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.

  5. Quantitative human gait analysis

    Microsoft Academic Search

    Vlasta Zanchi; Vladan Papic; Mojmil Cecic

    2000-01-01

    In this paper, the methodology for normal gait recognition and estimation is described. Normal gait recognition is derived on the basis of kinematics data of the human locomotion system. Measurements were carried out and the data were processed and statistically analyzed.The procedure was done on a group of 20 students. Kinematics data have been presented in phase plane. Sets of

  6. Recognition using gait.

    SciTech Connect

    Koch, Mark William

    2007-09-01

    Gait or an individual's manner of walking, is one approach for recognizing people at a distance. Studies in psychophysics and medicine indicate that humans can recognize people by their gait and have found twenty-four different components to gait that taken together make it a unique signature. Besides not requiring close sensor contact, gait also does not necessarily require a cooperative subject. Using video data of people walking in different scenarios and environmental conditions we develop and test an algorithm that uses shape and motion to identify people from their gait. The algorithm uses dynamic time warping to match stored templates against an unknown sequence of silhouettes extracted from a person walking. While results under similar constraints and conditions are very good, the algorithm quickly degrades with varying conditions such as surface and clothing.

  7. The effects of ankle mobilization and active stretching on the difference of weight-bearing distribution, low back pain and flexibility in pronated-foots subjects

    PubMed Central

    Yoon, Ki-Seok; Park, Seong-Doo

    2013-01-01

    The purpose of this study was designed to analyze the effects mobilization and active stretching on the difference of weight-bearing distribution, low back pain, and flexibility in pronated-foot subjects. The subjects of this study were 16 chronic low back pain patients. They were randomly divided into the control and experimental group. The experimental group had used the model of ankle mobilization and calf muscle active stretching three times per week, for 4 weeks. The control group did same method without an ankle mobilization. The range of flexion and extension motion of the lumbar vertebrae and low back pain degree and difference of weight-bearing were measured before and after the experiment. The model of ankle mobilization and calf muscle stretching of pronated-foot significantly improved the range of flexion and extension motion of the vertebrae. And the visual analogue scale and distribution of weight-bearing were decreased in both of two groups. In other word, the exercise of this study showed that the model of ankle mobilization and calf muscle stretching of pronated-foot had positive effects on improving the range of flexion and extension motion of the vertebrae. The calf muscle stretching was easy and it is effective in therapy that patients by themselves and helped to recover the balance of the vertebrae to combine ankle mobilization and muscle stretching. PMID:24278874

  8. Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  9. Gait Synthesis of Abnormal Gaits in Canines 

    E-print Network

    Playle, Amber

    2014-10-10

    analysis is used to isolate the components of canine gait that are the direct result of poor health. These components are then synthesized with the healthy motion of a new dog to create the appearance of the unhealthy motion in that breed. Given two...

  10. [Gait analysis in dogs].

    PubMed

    Off, W; Matis, U

    1997-01-01

    Gait analysis has found extensive application in human medicine in orthopaedics, rehabilitation and sports medicine. In veterinary medicine locomotor studies are focused on horses. The available dynamometric and kinemetric measurement systems and their application to tetrapods are discussed after a historical survey with literary review has been made. The installation of a gait analysis laboratory for small animals at the Department of Veterinary Surgery of the Ludwig-Maximilians-University of Munich and results of clinical studies including gait analysis will be presented. PMID:9157635

  11. In Vivo Motion of Femoral Condyles During Weight-Bearing Flexion After Anterior Cruciate Ligament Rupture Using Biplane Radiography

    PubMed Central

    Chen, Kaining; Yin, Li; Cheng, Liangjun; Li, Chuan; Chen, Cheng; Yang, Liu

    2013-01-01

    The purpose of this study was to investigate in vivo three- dimensional tibiofemoral kinematics and femoral condylar motion in knees with anterior cruciate ligament (ACL) deficiency during a knee bend activity. Ten patients with unilateral ACL rupture were enrolled. Both the injured and contralateral normal knees were imaged using biplane radiography at extension and at 15°, 30°, 60°, 90°, and 120° of flexion. Bilateral knees were next scanned by computed tomography, from which bilateral three-dimensional knee models were created. The in vivo tibiofemoral motion at each flexion position was reproduced through image registration using the knee models and biplane radiographs. A joint coordinate system containing the geometric center axis of the femur was used to measure the tibiofemoral motion. In ACL deficiency, the lateral femoral condyle was located significantly more posteriorly at extension and at 15° (p < 0.05), whereas the medial condylar position was changed only slightly. This constituted greater posterior translation and external rotation of the femur relative to the tibia at extension and at 15° (p < 0.05). Furthermore, ACL deficiency led to a significantly reduced extent of posterior movement of the lateral condyle during flexion from 15° to 60° (p < 0.05). Coupled with an insignificant change in the motion of the medial condyle, the femur moved less posteriorly with reduced extent of external rotation during flexion from 15° to 60° in ACL deficiency (p < 0.05). The medial- lateral and proximal-distal translations of the medial and lateral condyles and the femoral adduction-abduction rotation were insignificantly changed after ACL deficiency. The results demonstrated that ACL deficiency primarily changed the anterior-posterior motion of the lateral condyle, producing not only posterior subluxation at low flexion positions but also reduced extent of posterior movement during flexion from 15° to 60°. Key Points Three-dimensional tibiofemoral kinematics and femoral condylar motion in ACL-deficient knees during upright weight-bearing flexion were measured using biplane radiography with the geometric center axis. ACL deficiency caused posterior subluxation of the lateral condyle with excess external femoral rotation at early flexion positions. On flexion from 15° to 60°, the lateral condyle moved slightly posteriorly in ACL deficiency leading to reduced extent of external femoral rotation. PMID:24149168

  12. The role of exercise intensity in the bone metabolic response to an acute bout of weight-bearing exercise.

    PubMed

    Scott, Jonathan P R; Sale, Craig; Greeves, Julie P; Casey, Anna; Dutton, John; Fraser, William D

    2011-02-01

    We compared the effects of exercise intensity (EI) on bone metabolism during and for 4 days after acute, weight-bearing endurance exercise. Ten males [mean ± SD maximum oxygen uptake (Vo(2max)): 56.2 ± 8.1 ml·min(-1)·kg(-1)] completed three counterbalanced 8-day trials. Following three control days, on day 4, subjects completed 60 min of running at 55%, 65%, and 75% Vo(2max). Markers of bone resorption [COOH-terminal telopeptide region of collagen type 1 (?-CTX)] and formation [NH(2)-terminal propeptides of procollagen type 1 (P1NP), osteocalcin (OC), bone-alkaline phosphatase (ALP)], osteoprotegerin (OPG), parathyroid hormone (PTH), albumin-adjusted calcium (ACa), phosphate (PO(4)), and cortisol were measured during and for 3 h after exercise and on four follow-up days (FU1-FU4). At 75% Vo(2max), ?-CTX was not significantly increased from baseline by exercise but was higher compared with 55% (17-19%, P < 0.01) and 65% (11-13%, P < 0.05) Vo(2max) in the first hour postexercise. Concentrations were decreased from baseline in all three groups by 39-42% (P < 0.001) at 3 h postexercise but not thereafter. P1NP increased (P < 0.001) during exercise only, while bone-ALP was increased (P < 0.01) at FU3 and FU4, but neither were affected by EI. PTH and cortisol increased (P < 0.001) with exercise at 75% Vo(2max) only and were higher (P < 0.05) than at 55% and 65% Vo(2max) during and immediately after exercise. The increases (P < 0.001) in OPG, ACa, and PO(4) with exercise were not affected by EI. Increasing EI from 55% to 75% Vo(2max) during 60 min of running resulted in higher ?-CTX concentrations in the first hour postexercise but had no effect on bone formation markers. Increased bone-ALP concentrations at 3 and 4 days postexercise suggest a beneficial effect of this type of exercise on bone mineralization. The increase in OPG was not influenced by exercise intensity, whereas PTH was increased at 75% Vo(2max) only, which cannot be fully explained by changes in serum calcium or PO(4) concentrations. PMID:21127210

  13. Gait rehabilitation machines based on programmable footplates

    PubMed Central

    Schmidt, Henning; Werner, Cordula; Bernhardt, Rolf; Hesse, Stefan; Krüger, Jörg

    2007-01-01

    Background Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing. Results With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator) or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I). For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS) revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations. Conclusion Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles of motor relearning promoting a task-specific repetitive approach. Sophisticated technical developments and positive randomized controlled trials form the basis of a growing acceptance worldwide to the benefits or our patients. PMID:17291335

  14. Gait Analysis Using Wearable Sensors

    PubMed Central

    Tao, Weijun; Liu, Tao; Zheng, Rencheng; Feng, Hutian

    2012-01-01

    Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. PMID:22438763

  15. Importance of Gait Training

    MedlinePLUS

    ... all lower-limb amputees will bene?t from gait training at some point in their recovery to help ... the supervision of a physical therapist, the initial training is provided by the prosthetist as part of ...

  16. Ground reaction forces and plantar pressure distribution during occasional loaded gait.

    PubMed

    Castro, Marcelo; Abreu, Sofia; Sousa, Helena; Machado, Leandro; Santos, Rubim; Vilas-Boas, João Paulo

    2013-05-01

    This study compared the ground reaction forces (GRF) and plantar pressures between unloaded and occasional loaded gait. The GRF and plantar pressures of 60 participants were recorded during unloaded gait and occasional loaded gait (wearing a backpack that raised their body mass index to 30); this load criterion was adopted because is considered potentially harmful in permanent loaded gait (obese people). The results indicate an overall increase (absolute values) of GRF and plantar pressures during occasional loaded gait (p < 0.05); also, higher normalized (by total weight) values in the medial midfoot and toes, and lower values in the lateral rearfoot region were observed. During loaded gait the magnitude of the vertical GRF (impact and thrust maximum) decreased and the shear forces increased more than did the proportion of the load (normalized values). These data suggest a different pattern of GRF and plantar pressure distribution during occasional loaded compared to unloaded gait. PMID:23157973

  17. Comparison of Upright Gait with Supine Bungee-Cord Gait

    NASA Technical Reports Server (NTRS)

    Boda, Wanda L.; Hargens, Alan R.; Campbell, J. A.; Yang, C.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Running on a treadmill with bungee-cord resistance is currently used on the Russian space station MIR as a countermeasure for the loss of bone and muscular strength which occurs during spaceflight. However, it is unknown whether ground reaction force (GRF) at the feet using bungee-cord resistance is similar to that which occurs during upright walking and running on Earth. We hypothesized-that the DRAMs generated during upright walking and running are greater than the DRAMs generated during supine bungee-cord gait. Eleven healthy subjects walked (4.8 +/- 0.13 km/h, mean +/- SE) and ran (9.1 +/- 0.51 km/h) during upright and supine bungee-cord exercise on an active treadmill. Subjects exercised for 3 min in each condition using a resistance of 1 body weight calibrated during an initial, stationary standing position. Data were sampled at a frequency of 500Hz and the mean of 3 trials was analyzed for each condition. A repeated measures analysis of variance tested significance between the conditions. Peak DRAMs during upright walking were significantly greater (1084.9 +/- 111.4 N) than during supine bungee-cord walking (770.3 +/- 59.8 N; p less than 0.05). Peak GRFs were also significantly greater for upright running (1548.3 +/- 135.4 N) than for supine bungee-cord running (1099.5 +/- 158.46 N). Analysis of GRF curves indicated that forces decreased throughout the stance phase for bungee-cord gait but not during upright gait. These results indicate that bungee-cord exercise may not create sufficient loads at the feet to counteract the loss of bone and muscular strength that occurs during long-duration exposure to microgravity.

  18. Gait Analysis in a Rat Model of Osteoarthrosis

    Microsoft Academic Search

    K. A Clarke; S. A Heitmeyer; A. G Smith; Y. O Taiwo

    1997-01-01

    Gait analysis has been undertaken in a rat model of osteoarthrosis, induced by intra-articular injection of sodium iodoacetate into the left knee. Two weeks after injection, no disturbances were recorded to the velocity of locomotion, the stride length nor the stride, stance, or swing times. However, clear and consistent reductions in the peak vertical load bearing (Pz) by the affected

  19. Exercises to Improve Gait Abnormalities

    MedlinePLUS

    ... Home About Goals Articles Directories Videos Resources Contact Exercises to Improve Gait Abnormalities Home » Article Categories » Exercise and Fitness Font Size: A A A A Exercises to Improve Gait Abnormalities Next Page The manner ...

  20. Effects of Backpack Carriage on Gait and Posture-Design Studies

    Microsoft Academic Search

    Sonal Atreya; Deepak Joshi; Sneh Anand; U. Singh; Rahul Ribeiro

    \\u000a Carrying heavy loads is known to cause a change in the gait. This study examines the gait pattern in subjects carrying backpack\\u000a of 15% of their body weight while walking on a force platform. Relationship between gait and synchronous beats was explored\\u000a by conducting experiments where the subjects walked to synchronized beats while carrying load to see the impact of

  1. Evaluation of knee joint muscle forces and tissue stresses-strains during gait in severe OA versus normal subjects.

    PubMed

    Adouni, M; Shirazi-Adl, A

    2014-01-01

    Osteoarthritis (OA) is the leading cause of pain and disability in the elderly with the knee being the most affected weight bearing joint. We used a musculoskeletal biomechanical model of the lower extremity including a detailed validated knee joint finite element model to compute lower extremity muscle forces and knee joint stresses-strains during the stance phase of gait. The model was driven by gait data on OA patients, and results were compared with those of the same model driven by data on normal controls. Additional analyses were performed with altered cartilage-menisci properties to evaluate the effects of deterioration during OA. In OA patients compared to normal subjects, muscle forces dropped at nearly all stance periods except mid-stance. Force in the anterior cruciate ligament remained overall the same. Total contact forces-stresses deceased by about 25%. Alterations in properties due to OA had negligible effects on muscle forces, but increased contact areas and cartilage strains and reduced contact pressures. Reductions in contact stresses and increases in tissue strains and transfer of load via menisci are partly due to the altered kinetics-kinematics of gait and partly due to deterioration in cartilage-menisci properties in OA patients. PMID:24038150

  2. Gait Analysis for Human Identification

    Microsoft Academic Search

    Amit A. Kale; Naresh P. Cuntoor; B. Yegnanarayana; A. N. Rajagopalan; Rama Chellappa

    2003-01-01

    Human gait is an attractive modality for recognizing people at a dis- tance. In this paper we adopt an appearance-based approach to the problem of gait recognition. The width of the outer contour of the binarized silhouette of a walking person is chosen as the basic image feature. Different gait features are extracted from the width vector such as the

  3. Effect of Weight-bearing Therapeutic Exercise on the Q-angle and Muscle Activity Onset Times of Elite Athletes with Patellofemoral Pain Syndrome: A Randomized Controlled Trial

    PubMed Central

    Lee, Jehoon; Lee, Hwangjae; Lee, Wanhee

    2014-01-01

    [Purpose] The purpose of this study was to determine the effect of a weight-bearing therapeutic exercise program for elite athletes diagnosed as having patellofemoral pain syndrome (PFPS). [Subjects] The subjects were 34 elite athletes from the Seoul T Center. They were randomly allocated to three groups: an elastic band exercise group (EBG), a sling exercise group (SEG), or a control group (CG). [Methods] Therapeutic exercises were performed 3 times a week for 8 weeks. The visual analogue scale (VAS) hamstring length, and static and dynamic Q angles were used to test the exercise effect of the exercises, as well as the onset time of electromyographic activity of vastus medialis oblique (VMO) and vastus lateralis (VL). [Results] Decrease of the dynamic Q-angle in EBG was significant and significantly greater than that in CG. The decrease in VAS in SEG was significant and significantly greater than that in CG. There were significant differences in the VL and VMO activity onset times in SEG between pre- and post-test, and their differences between pre- and post-test were also significantly different. [Conclusion] Weight-bearing therapeutic exercise is hoped that clinicians will use this information for better implementation of effective exercise methods for elite athletes with PFPS. PMID:25140080

  4. In vivo regulation of the beta-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats

    NASA Technical Reports Server (NTRS)

    Giger, J. M.; Haddad, F.; Qin, A. X.; Baldwin, K. M.

    2000-01-01

    In the weight-bearing hindlimb soleus muscle of the rat, approximately 90% of muscle fibers express the beta-myosin heavy chain (beta-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from beta toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the beta-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length beta-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest beta-promoter fragment (-3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the -3500-, -914-, and -408-bp promoter constructs were significantly reduced ( approximately 40%), compared with the control muscles. However, using the -215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the -408 and -215 bp of the promoter.

  5. Identification of muscle synergies associated with gait transition in humans

    PubMed Central

    Hagio, Shota; Fukuda, Mizuho; Kouzaki, Motoki

    2015-01-01

    There is no theoretical or empirical evidence to suggest how the central nervous system (CNS) controls a variety of muscles associated with gait transition between walking and running. Here, we examined the motor control during a gait transition based on muscle synergies, which modularly organize functionally similar muscles. To this end, the subjects walked or ran on a treadmill and performed a gait transition spontaneously as the treadmill speed increased or decreased (a changing speed condition) or voluntarily following an experimenter’s instruction at constant treadmill speed (a constant speed condition). Surface electromyograms (EMGs) were recorded from 11 lower limb muscles bilaterally. We then extracted the muscle weightings of synergies and their activation coefficients from the EMG data using non-negative matrix factorization. As a result, the gait transition was controlled by approximately 9 muscle synergies, which were common during a walking and running, and their activation profiles were changed before and after a gait transition. Near a gait transition, the peak activation phases of the synergies, which were composed of plantar flexor muscles, were shifted to an earlier phase at the walk-to-run transition, and vice versa. The shifts were gradual in the changing speed condition, but an abrupt change was observed in the constant speed condition. These results suggest that the CNS low-dimensionally regulate the activation profiles of the specific synergies based on afferent information (spontaneous gait transition) or by changing only the descending neural input to the muscle synergies (voluntary gait transition) to achieve a gait transition. PMID:25713525

  6. Regression analysis of gait parameters with speed in normal children walking at self-selected speeds

    Microsoft Academic Search

    B. W. Stansfield; S. J. Hillman; M. E. Hazlewood; J. E. Robb

    2006-01-01

    Dimensionless analysis ensures that differences in sizes (e.g. height and weight) of children have a minimal influence on gait parameters. The results of changes in speed on gait parameters were examined using dimensionless analysis on data from a prospective 5-year study of 16 children. Linear regression analysis of peak and trough values of temporal distance parameters, ground reaction forces, joint

  7. A treadmill apparatus and harness support for evaluation and rehabilitation of gait

    Microsoft Academic Search

    Kathleen E. Norman; André Pepin; Michel Ladouceur; Hugues Barbeau

    1995-01-01

    This report describes a treadmill apparatus for the evaluation and rehabilitation of gait in disabled persons. The apparatus incorporates a body weight support system as well as mechanisms to change certain conditions: treadmill belt speed, upward-downward and lateral slopes, and provision of obstacles. The apparatus enables elements of a treadmill walking pattern to be visible in persons for whom gait

  8. Effective one step-iterative fiducial marker-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

    Choi, Jang-Hwan; Maier, Andreas; Berger, Martin; Fahrig, Rebecca

    2014-03-01

    We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients' involuntary motion in the lower body during weight-bearing Carm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landwebertype iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.

  9. Reliability of the measures of weight-bearing distribution obtained during quiet stance by digital scales in subjects with and without hemiparesis.

    PubMed

    de Araujo-Barbosa, Paulo Henrique Ferreira; de Menezes, Lidiane Teles; Costa, Abraão Souza; Couto Paz, Clarissa Cardoso Dos Santos; Fachin-Martins, Emerson

    2015-05-01

    Described as an alternative way of assessing weight-bearing asymmetries, the measures obtained from digital scales have been used as an index to classify weight-bearing distribution. This study aimed to describe the intra-test and the test/retest reliability of measures in subjects with and without hemiparesis during quiet stance. The percentage of body weight borne by one limb was calculated for a sample of subjects with hemiparesis and for a control group that was matched by gender and age. A two-way analysis of variance was used to verify the intra-test reliability. This analysis was calculated using the differences between the averages of the measures obtained during single, double or triple trials. The intra-class correlation coefficient (ICC) was utilized and data plotted using the Bland-Altman method. The intra-test analysis showed significant differences, only observed in the hemiparesis group, between the measures obtained by single and triple trials. Excellent and moderate ICC values (0.69-0.84) between test and retest were observed in the hemiparesis group, while for control groups ICC values (0.41-0.74) were classified as moderate, progressing from almost poor for measures obtained by a single trial to almost excellent for those obtained by triple trials. In conclusion, good reliability ranging from moderate to excellent classifications was found for participants with and without hemiparesis. Moreover, an improvement of the repeatability was observed with fewer trials for participants with hemiparesis, and with more trials for participants without hemiparesis. PMID:25541319

  10. A mechanical energy analysis of gait initiation

    Microsoft Academic Search

    Christopher A. Miller; Mary C. Verstraete

    1999-01-01

    The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in

  11. Oxidation of UltraHigh Molecular Weight Polyethylene and Its Influence on Contact Fatigue and Pitting of Knee Bearings

    Microsoft Academic Search

    F. E. Kennedy; B. H. Currier; D. W. Van Citters; J. H. Currier; J. P. Collier; M. B. Mayor

    2003-01-01

    Tibial hearings of total knee replacements are generally made from ultra-high molecular weight polyethylene (UHMWPE). Failure of those hearings has been found to result in many cases from subsurface crack initiation and propagation. Two types of subsurface-originated failure modes are investigated in this study: macroscopic contact fatigue and microscopic pitting. The cracks responsible for both modes of failure initiate in

  12. Assessment of motion of a swing leg and gait rehabilitation with a gravity balancing exoskeleton.

    PubMed

    Agrawal, Sunil K; Banala, Sai K; Fattah, Abbas; Sangwan, Vivek; Krishnamoorthy, Vijaya; Scholz, John P; Hsu, Wei-Li

    2007-09-01

    The gravity balancing exoskeleton, designed at University of Delaware, Newark, consists of rigid links, joints and springs, which are adjustable to the geometry and inertia of the leg of a human subject wearing it. This passive exoskeleton does not use any motors but is designed to unload the human leg joints from the gravity load over its range-of-motion. The underlying principle of gravity balancing is to make the potential energy of the combined leg-machine system invariant with configuration of the leg. Additionally, parameters of the exoskeleton can be changed to achieve a prescribed level of gravity assistance, from 0% to 100%. The goal of the results reported in this paper is to provide preliminary quantitative assessment of the changes in kinematics and kinetics of the walking gait when a human subject wears such an exoskeleton. The data on kinematics and kinetics were collected on four healthy and three stroke patients who wore this exoskeleton. These data were computed from the joint encoders and interface torque sensors mounted on the exoskeleton. This exoskeleton was also recently used for a six-week training of a chronic stroke patient, where the gravity assistance was progressively reduced from 100% to 0%. The results show a significant improvement in gait of the stroke patient in terms of range-of-motion of the hip and knee, weight bearing on the hemiparetic leg, and speed of walking. Currently, training studies are underway to assess the long-term effects of such a device on gait rehabilitation of hemiparetic stroke patients. PMID:17894273

  13. Generalized low bone mass of girls with adolescent idiopathic scoliosis is related to inadequate calcium intake and weight bearing physical activity in peripubertal period.

    PubMed

    Lee, Warren T K; Cheung, Catherine S K; Tse, Yee Kit; Guo, Xia; Qin, Ling; Ho, Suzanne C; Lau, Joseph; Cheng, Jack C Y

    2005-09-01

    Generalized low bone mass has been well documented in patients with adolescent idiopathic scoliosis (AIS). However, studies linking calcium-intake (CA), weight-bearing physical-activity (PA) and bone mass of AIS are lacking. We aimed to study the relationship between CA, PA and bone mass in AIS girls and compared to those of healthy non-AIS controls during the peripubertal period. Newly diagnosed AIS girls (n=596) aged 11-16 years with Cobb angle >/=10 degrees were recruited to compare with age-matched healthy girls (n=302) in a cross-sectional study. Anthropometric parameters, pubertal status, CA and PA were assessed. Areal bone mass of lumbar spine and femoral neck, and volumetric bone mass of distal radius and tibia were determined by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. The results showed that weight and body mass index (BMI) of AIS were lower than the controls (P<0.05). Corrected height and arm span of AIS were longer than those of controls from 13 years onwards (P<0.02). Median CA of AIS was <410 mg/day across the ages and did not differ from the controls (P=0.063). Median PA of AIS (1.6 h/day) was lower than the controls (1.8 h/day) (P=0.025). Bone mass of AIS was on average 6.5% lower than controls across the ages (P<0.05). CA and PA were significantly correlated with bone mass of AIS (P<0.04). Multivariate analysis showed that AIS in girls was associated with lower bone mass, and that both CA and PA were independent predictors of bone mass in AIS. In conclusion, AIS girls were found to have lower body weight and BMI, longer segmental lengths and generalized low bone mass. Inadequate calcium intake and weight-bearing physical activity were significantly associated with low bone mass in AIS girls during the peripubertal period. The importance of preventing generalized osteopenia in the control of AIS progression during the peripubertal period warrants further study. PMID:15726296

  14. Effects of a lower-body exoskeleton device on metabolic cost and gait biomechanics during load carriage.

    PubMed

    Gregorczyk, Karen N; Hasselquist, Leif; Schiffman, Jeffrey M; Bensel, Carolyn K; Obusek, John P; Gutekunst, David J

    2010-10-01

    This study investigated the effects on metabolic cost and gait biomechanics of using a prototype lower-body exoskeleton (EXO) to carry loads. Nine US Army participants walked at 1.34 m/s on a 0% grade for 8 min carrying military loads of 20 kg, 40 kg and 55 kg with and without the EXO. Mean oxygen consumption (VO(2)) scaled to body mass and scaled to total mass were significantly higher, by 60% and 41% respectively, when the EXO was worn, compared with the control condition. Mean VO(2) and mean VO(2) scaled to body mass significantly increased with load. The kinematic and kinetic data revealed significant differences between EXO and control conditions, such as walking with a more flexed posture and braking with higher ground reaction force at heel strike when wearing the EXO. Study findings demonstrate that the EXO increased users' metabolic cost while carrying various loads and altered their gait biomechanics compared with conventional load carriage. STATEMENT OF RELEVANCE: An EXO designed to assist in load bearing was found to raise energy expenditure substantially when tested by soldiers carrying military loads. EXO weight, weight distribution and design elements that altered users' walking biomechanics contributed to the high energy cost. To realise the potential of EXOs, focus on the user must accompany engineering advances. PMID:20865609

  15. `An observational report of intensive robotic and manual gait training in sub-acute stroke

    PubMed Central

    2012-01-01

    Background The use of automated electromechanical devices for gait training in neurological patients is increasing, yet the functional outcomes of well-defined training programs using these devices and the characteristics of patients that would most benefit are seldom reported in the literature. In an observational study of functional outcomes, we aimed to provide a benchmark for expected change in gait function in early stroke patients, from an intensive inpatient rehabilitation program including both robotic and manual gait training. Methods We followed 103 sub-acute stroke patients who met the clinical inclusion criteria for Body Weight Supported Robotic Gait Training (BWSRGT). Patients completed an intensive 8-week gait-training program comprising robotic gait training (weeks 0-4) followed by manual gait training (weeks 4-8). A change in clinical function was determined by the following assessments taken at 0, 4 and 8 weeks (baseline, mid-point and end-point respectively): Functional Ambulatory Categories (FAC), 10 m Walking Test (10 MWT), and Tinetti Gait and Balance Scales. Results Over half of the patients made a clinically meaningful improvement on the Tinetti Gait Scale (> 3 points) and Tinetti Balance Scale (> 5 points), while over 80% of the patients increased at least 1 point on the FAC scale (0-5) and improved walking speed by more than 0.2 m/s. Patients responded positively in gait function regardless of variables gender, age, aetiology (hemorrhagic/ischemic), and affected hemisphere. The most robust and significant change was observed for patients in the FAC categories two and three. The therapy was well tolerated and no patients withdrew for factors related to the type or intensity of training. Conclusions Eight-weeks of intensive rehabilitation including robotic and manual gait training was well tolerated by early stroke patients, and was associated with significant gains in function. Patients with mid-level gait dysfunction showed the most robust improvement following robotic training. PMID:22329866

  16. Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training

    Microsoft Academic Search

    Alexander Duschau-Wicke; Andrea Caprez; Robert Riener

    2010-01-01

    BACKGROUND: Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on

  17. Gait recognition and walking exercise intensity estimation.

    PubMed

    Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

    2014-04-01

    Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients' exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients' attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

  18. Expressing gait-line symmetry in able-bodied gait

    PubMed Central

    Jele?, Piotr; Wit, Andrzej; Dudzi?ski, Krzysztof; Nolan, Lee

    2008-01-01

    Background Gait-lines, or the co-ordinates of the progression of the point of application of the vertical ground reaction force, are a commonly reported parameter in most in-sole measuring systems. However, little is known about what is considered a "normal" or "abnormal" gait-line pattern or level of asymmetry. Furthermore, no reference databases on healthy young populations are available for this parameter. Thus the aim of this study is to provide such reference data in order to allow this tool to be better used in gait analysis. Methods Vertical ground reaction force data during several continuous gait cycles were collected using a Computer Dyno Graphy in-sole system® for 77 healthy young able-bodied subjects. A curve (termed gait-line) was obtained from the co-ordinates of the progression of the point of application of the force. An Asymmetry Coefficient Curve (AsC) was calculated between the mean gait-lines for the left and right foot for each subject. AsC limits of ± 1.96 and 3 standard deviations (SD) from the mean were then calculated. Gait-line data from 5 individual subjects displaying pathological gait due to disorders relating to the discopathy of the lumbar spine (three with considerable plantarflexor weakness, two with considerable dorsiflexor weakness) were compared to the AsC results from the able-bodied group. Results The ± 1.96 SD limit suggested that non-pathological gait falls within 12–16% asymmetry for gait-lines. Those exhibiting pathological gait fell outside both the ± 1.96 and ± 3SD limits at several points during stance. The subjects exhibiting considerable plantarflexor weakness all fell outside the ± 1.96SD limit from 30–50% of foot length to toe-off while those exhibiting considerable dorsiflexor weakness fell outside the ± 1.96SD limit between initial contact to 25–40% of foot length, and then surpassed the ± 3SD limit after 55–80% of foot length. Conclusion This analysis of gait-line asymmetry provides a reference database for young, healthy able-bodied subject populations for both further research and clinical gait analysis. This information is used to suggest non-pathological gait-line asymmetry pattern limits, and limits where detailed case analysis is warranted. PMID:19099568

  19. Genetic Algorithms for Gait Synthesis in a Hexapod Robot

    E-print Network

    Portland State University

    Genetic Algorithms for Gait Synthesis in a Hexapod Robot M. Anthony Lewis, Andrew H. Fagg-legged walking robot. The CPG is composed of a network of neurons. In contrast to the main stream work in neural networks, the interconnection weights are altered by a Genetic Algo- rithm (GA), rather than a learning

  20. Virtual Reality in Gait Rehabilitation Nigel W. Tierney1

    E-print Network

    Crouch, Jessica R.

    , Virginia USA 5 Department of Medical Laboratory Sciences, Old Dominion University, Virginia USA Abstract- Gait system that has been developed consists of VR software that generates and displays a dynamic urban with an overhead suspension device that can provide a patient with partial weight support. Inertial tracking

  1. Pioglitazone Treatment Increases Survival and Prevents Body Weight Loss in Tumor–Bearing Animals: Possible Anti-Cachectic Effect

    PubMed Central

    Beluzi, Mércia; Peres, Sidney B.; Henriques, Felipe S.; Sertié, Rogério A. L.; Franco, Felipe O.; Santos, Kaltinaitis B.; Knobl, Pâmela; Andreotti, Sandra; Shida, Cláudio S.; Neves, Rodrigo X.; Farmer, Stephen R.; Seelaender, Marília; Lima, Fábio B.; Batista Jr., Miguel L.

    2015-01-01

    Cachexia is a multifactorial syndrome characterized by profound involuntary weight loss, fat depletion, skeletal muscle wasting, and asthenia; all symptoms are not entirely attributable to inadequate nutritional intake. Adipose tissue and skeletal muscle loss during cancer cachexia development has been described systematically. The former was proposed to precede and be more rapid than the latter, which presents a means for the early detection of cachexia in cancer patients. Recently, pioglitazone (PGZ) was proposed to exhibit anti-cancer properties, including a reduction in insulin resistance and adipose tissue loss; nevertheless, few studies have evaluated its effect on survival. For greater insight into a potential anti-cachectic effect due to PGZ, 8-week-old male Wistar rats were subcutaneously inoculated with 1 mL (2×107) of Walker 256 tumor cells. The animals were randomly assigned to two experimental groups: TC (tumor + saline-control) and TP5 (tumor + PGZ/5 mg). Body weight, food ingestion and tumor growth were measured at baseline and after removal of tumor on days 7, 14 and 26. Samples from different visceral adipose tissue (AT) depots were collected on days 7 and 14 and stored at -80o C (5 to 7 animals per day/group). The PGZ treatment showed an increase in the survival average of 27.3% (P< 0.01) when compared to TC. It was also associated with enhanced body mass preservation (40.7 and 56.3%, p< 0.01) on day 14 and 26 compared with the TC group. The treatment also reduced the final tumor mass (53.4%, p<0.05) and anorexia compared with the TC group during late-stage cachexia. The retroperitoneal AT (RPAT) mass was preserved on day 7 compared with the TC group during the same experimental period. Such effect also demonstrates inverse relationship with tumor growth, on day 14. Gene expression of PPAR-?, adiponectin, LPL and C/EBP-? from cachectic rats was upregulated after PGZ. Glucose uptake from adipocyte cells (RPAT) was entirely re-established due to PGZ treatment. Taken together, the results demonstrate beneficial effects of PGZ treatment at both the early and final stages of cachexia. PMID:25807446

  2. Gait festination in Parkinson's disease

    Microsoft Academic Search

    N Giladi; H Shabtai; E Rozenberg; E Shabtai

    2001-01-01

    Background: Festinating gait (FSG) was first associated with parkinsonism by Sir James Parkinson, in his original essay on “The Shaking Palsy”. Its frequency and relation to other parkinsonian features have never been assessed.Objective: To study the relationships between gait festination and other parkinsonian clinical features among patients with Parkinson's disease (PD).Method: During an open lecture to patients with PD who

  3. Gait Analysis and the Bootstrap

    Microsoft Academic Search

    Richard A. Olshen; Edmund N. Biden; Marilynn P. Wyatt; David H. Sutherland

    1989-01-01

    This paper is about random coefficient trigonometric regression models and their use in gait analysis. Here gait analysis means free-speed walking on a level surface. Our study focuses on bootstrap-based prediction regions for the angular rotation curves of test children, when the relevant training data are gathered from normal children of comparable ages. Considerations that led to our choice of

  4. Gait analysis methods in rehabilitation

    Microsoft Academic Search

    Richard Baker; Hugh Williamson; Gait CCRE

    2006-01-01

    INTRODUCTION: Brand's four reasons for clinical tests and his analysis of the characteristics of valid biomechanical tests for use in orthopaedics are taken as a basis for determining what methodologies are required for gait analysis in a clinical rehabilitation context. MEASUREMENT METHODS IN CLINICAL GAIT ANALYSIS: The state of the art of optical systems capable of measuring the positions of

  5. Clinical gait analysis: A review

    Microsoft Academic Search

    Michael W. Whittle

    1996-01-01

    Gait analysis has now advanced to the point where it is used as a routine part of patient management in certain centers. It is best thought of as a special investigation, which is used together with the history, physical examination and other special investigations to perform a detailed assessment of a patient with a walking disorder. Clinical gait analysis usually

  6. Gait termination: a review of experimental methods and the effects of ageing and gait pathologies

    Microsoft Academic Search

    W. A. Sparrow; Oren Tirosh

    2005-01-01

    The study of human gait has expanded and diversified to the extent that it is now possible to identify a substantive literature concerning a variety of gait tasks, such as gait initiation [Halliday SE, Winter DA, Frank JS, Patla AE, Prince F. The initiation of gait in young, elderly, and Parkinson's disease subjects. Gait Posture 1998;8:8–14; Mickelborough J, van der

  7. Towards Scalable View-Invariant Gait Recognition: Multilinear Analysis for Gait

    E-print Network

    Lee, Chan-Su

    395 Towards Scalable View-Invariant Gait Recognition: Multilinear Analysis for Gait Chan-Su Lee. In this paper we introduce a novel approach for learning view-inva- riant gait representation that does decomposition which decomposes view factors, body configuration factors, and gait-style factors. Gait

  8. Two-Point Gait: Decoupling Gait from Body Shape Stephen Lombardi, Ko Nishino

    E-print Network

    Nishino, Ko

    , for instance, inherently entangle body shape and gait. For gait analysis and recog- nition, decouplingTwo-Point Gait: Decoupling Gait from Body Shape Stephen Lombardi, Ko Nishino Drexel University, Japan {makihara,yagi}@am.sanken.osaka-u.ac.jp Abstract Human gait modeling (e.g., for person

  9. Geometric moments for gait description

    NASA Astrophysics Data System (ADS)

    Toxqui-Quitl, C.; Morales-Batalla, V.; Padilla-Vivanco, A.; Camacho-Bello, C.

    2013-09-01

    The optical flow associated with a set of digital images of a moving individual is analyzed in order to extract a gait signature. For this, invariant Hu moments are obtained for image description. A Hu Moment History (HMH) is obtained from K frames to describe the gait signature of individuals in a video. The gait descriptors are subsequences of the HMH of variable width. Each subsequence is generated by means of genetic algorithms and used for classification in a neuronal network. The database for algorithm evaluation is MoBo, and the gait classification results are above 90% for the cases of slow and fast walking and 100% for the cases of walking with a ball and inclined walking. An optical processor is also implemented in order to obtain the descriptors of the human gait.

  10. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment

    SciTech Connect

    Choi, Jang-Hwan [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Maier, Andreas; Keil, Andreas; McWalter, Emily J.; Gold, Garry E.; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pal, Saikat [Biomedical Engineering Department, California Polytechnic State University, San Luis Obispo, California 93407 (United States)] [Biomedical Engineering Department, California Polytechnic State University, San Luis Obispo, California 93407 (United States); Beaupré, Gary S. [Musculoskeletal Research Laboratory, VA Palo Alto Health Care System, Palo Alto, California 94304 (United States)] [Musculoskeletal Research Laboratory, VA Palo Alto Health Care System, Palo Alto, California 94304 (United States)

    2014-06-15

    Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjectsin vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D warping improved the SSIM in the central slice by 20.22%, 16.83%, and 25.77% in the data with the largest motion among the five datasets (SCAN5); improvement in off-center slices was 18.94%, 29.14%, and 36.08%, respectively. Conclusions: The authors showed that C-arm CT control can be implemented for nonstandard horizontal trajectories which enabled us to scan and successfully reconstruct both legs of volunteers in weight-bearing positions. As predicted using theoretical models, the proposed motion correction methods improved image quality by reducing motion artifacts in reconstructions; 3D warping performed better than the 2D methods, especially in off-center slices.

  11. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment

    PubMed Central

    Choi, Jang-Hwan; Maier, Andreas; Keil, Andreas; Pal, Saikat; McWalter, Emily J.; Beaupré, Gary S.; Gold, Garry E.; Fahrig, Rebecca

    2014-01-01

    Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjects in vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D warping improved the SSIM in the central slice by 20.22%, 16.83%, and 25.77% in the data with the largest motion among the five datasets (SCAN5); improvement in off-center slices was 18.94%, 29.14%, and 36.08%, respectively. Conclusions: The authors showed that C-arm CT control can be implemented for nonstandard horizontal trajectories which enabled us to scan and successfully reconstruct both legs of volunteers in weight-bearing positions. As predicted using theoretical models, the proposed motion correction methods improved image quality by reducing motion artifacts in reconstructions; 3D warping performed better than the 2D methods, especially in off-center slices. PMID:24877813

  12. A bioengineering analysis of force actions at the knee in normal and pathological gait.

    PubMed

    Harrington, I J

    1976-05-01

    The paper describes a simplified bioengineering analysis for the determination of force actions at the knee joint for normal and pathological gaits. The stance phase of the gait cycle only is considered, and gravitational and inertia forces are excluded from the analysis. The anatomical and functional assumptions required for analysis are discussed. Force actions transmitted at the knee joint by the bearing surfaces, muscles and ligaments for normal individuals are presented with reference to magnitude and phasic relationship for the activity of level walking. Bearing loads transmitted at the knee joints of pathological limbs are also discussed. PMID:1276337

  13. Biology of gait control

    PubMed Central

    Annweiler, C.; Verghese, J.; Fantino, B.; Herrmann, F.R.; Allali, G.

    2011-01-01

    Background: Adverse neuromuscular events have been described in case of low serum 25-hydroxyvitamin D (25OHD) concentrations, suggesting that vitamin D may be involved in gait stability. The objective of this cross-sectional study was to examine the association between stride-to-stride variability of stride time (STV) and serum 25OHD concentration in adults aged 65 years and older. Methods: STV and 25OHD concentration were assessed in 411 community-dwelling older adults (mean age 70.4 ± 1.8 years, 57.9% women). The following established 25OHD thresholds were used: severe 25OHD insufficiency <10 ng/mL, moderate 10–30 ng/mL, and normal >30 ng/mL. Age, number of drugs used per day, use of psychoactive drugs, depressive symptoms, cognitive decline, history of falls, distance visual acuity, lower limb proprioception, center of mass (CoM) motion, and walking speed were considered as potential confounders. Results: A total of 16.6% (n = 68) of subjects had severe 25OHD insufficiency, 70.3% (n = 289) moderate insufficiency, and 13.1% (n = 54) normal concentrations. In the full adjusted and the stepwise backward linear regression models, high STV (worse performance) was associated with severe 25OHD insufficiency (p = 0.028 and p = 0.044, respectively), high CoM motion (p = 0.031 and p = 0.014, respectively), and low lower limb proprioception score (p = 0.017 and p = 0.008, respectively). The stepwise backward regression model also showed that high STV was associated with female gender (p = 0.041). Conclusions: Low serum 25OHD concentrations were associated with high STV reflecting a disturbed gait control. This association could be explained by a possible action of vitamin D on different components involved in gait control. PMID:21471466

  14. Effects of acceleration on gait measures in three horse gaits.

    PubMed

    Nauwelaerts, Sandra; Zarski, Lila; Aerts, Peter; Clayton, Hilary

    2015-05-01

    Animals switch gaits according to locomotor speed. In terrestrial locomotion, gaits have been defined according to footfall patterns or differences in center of mass (COM) motion, which characterizes mechanisms that are more general and more predictive than footfall patterns. This has generated different variables designed primarily to evaluate steady-speed locomotion, which is easier to standardize in laboratory conditions. However, in the ecology of an animal, steady-state conditions are rare and the ability to accelerate, decelerate and turn is essential. Currently, there are no data available that have tested whether COM variables can be used in accelerative or decelerative conditions. This study used a data set of kinematics and kinetics of horses using three gaits (walk, trot, canter) to evaluate the effects of acceleration (both positive and negative) on commonly used gait descriptors. The goal was to identify variables that distinguish between gaits both at steady state and during acceleration/deceleration. These variables will either be unaffected by acceleration or affected by it in a predictable way. Congruity, phase shift and COM velocity angle did not distinguish between gaits when the dataset included trials in unsteady conditions. Work (positive and negative) and energy recovery distinguished between gaits and showed a clear relationship with acceleration. Hodographs are interesting graphical representations to study COM mechanics, but they are descriptive rather than quantitative. Force angle, collision angle and collision fraction showed a U-shaped relationship with acceleration and seem promising tools for future research in unsteady conditions. PMID:25767145

  15. Bone peg fixation of a large chondral fragment in the weight-bearing portion of the lateral femoral condyle in an adolescent: a case report

    PubMed Central

    2014-01-01

    Introduction Chondral fracture of the knee is relatively rare and the optimal treatment option for this injury is still controversial. In this report, we present the case of a patient with this injury who was treated surgically using the bone peg fixation procedure. There has been no literature reporting the use of this technique for fixation of a detached chondral fragment. Case presentation The patient was a 14-year-old Japanese boy who sustained a knee injury while kicking a soccer ball. Although routine radiographs showed no abnormality, magnetic resonance imaging showed a large full-thickness chondral defect in the weight-bearing portion of his lateral femoral condyle and a detached chondral fragment in the anterior region. The size of the defect (fragment) was 2cm by 1.5cm. At surgery, the chondral fragment was fixed with eight cortical bone pegs that were harvested from the anteromedial aspect of his tibia. Conclusions The postoperative magnetic resonance imaging at 4 months and the second-look arthroscopy at 12 months revealed apparent healing of the fragment. In the final follow-up examination at 26 months, a physical examination showed no swelling with recovery of full range of motion, and he could play soccer at the pre-injury level with no complaint. Based on the clinical course of this patient, it is thought that bone peg fixation can be a valuable option for fixation of a large chondral fracture of the knee. PMID:25248689

  16. Terminology and forensic gait analysis.

    PubMed

    Birch, Ivan; Vernon, Wesley; Walker, Jeremy; Young, Maria

    2015-07-01

    The use of appropriate terminology is a fundamental aspect of forensic gait analysis. The language used in forensic gait analysis is an amalgam of that used in clinical practice, podiatric biomechanics and the wider field of biomechanics. The result can often be a lack of consistency in the language used, the definitions used and the clarity of the message given. Examples include the use of 'gait' and 'walking' as synonymous terms, confusion between 'step' and 'stride', the mixing of anatomical, positional and pathological descriptors, and inability to describe appropriately movements of major body segments such as the torso. The purpose of this paper is to share the well-established definitions of the fundamental parameters of gait, common to all professions, and advocate their use in forensic gait analysis to establish commonality. The paper provides guidance on the selection and use of appropriate terminology in the description of gait in the forensic context. This paper considers the established definitions of the terms commonly used, identifies those terms which have the potential to confuse readers, and suggests a framework of terminology which should be utilised in forensic gait analysis. PMID:26087876

  17. Effect of load carriage on gait due to firefighting air bottle configuration.

    PubMed

    Park, Kiwon; Hur, Pilwon; Rosengren, Karl S; Horn, Gavin P; Hsiao-Wecksler, Elizabeth T

    2010-07-01

    The air bottle configuration (mass and size) used with a firefighter's self-contained breathing apparatus may affect functional gait performance and slip/trip/fall risk, contributing to one of the most common and costly fire ground injuries to this population. To examine the potential effect of bottle mass and size on firefighter gait performance, four 30-min air bottle configurations were tested. To quantify biomechanical gait performance, kinetic and kinematic gait data were collected on 24 male firefighters while walking at normal and fast speeds during three conditions (no obstacle, 10 cm or 30 cm stationary obstacle). Bottle mass, obstacle height and walking speed - but not bottle size - were found to significantly impact gait parameters. Ten subjects (42%) contacted the taller obstacle while wearing heavier bottles, suggesting greater risk for tripping. Heavier bottles also resulted in larger forces by the trailing leg in both the anterior-posterior and vertical directions, suggesting greater risk for slipping. These results suggest that increased bottle weight may result in a decrease in gait performance and an increase in fall risk. STATEMENT OF RELEVANCE: Occupations, such as firefighting, often require use of a self-contained breathing apparatus that includes a pressurised air bottle. No systematic assessment has investigated how modest changes in load carriage due to bottle configuration (mass and size) might affect gait behaviour, especially when crossing obstacles. Bottle mass, but not size, was found to decrease gait performance and increase fall risk. PMID:20582769

  18. Gait and dementia: moving beyond the notion of gait apraxia

    Microsoft Academic Search

    R. J. Elble

    2007-01-01

    Summary  Highest level gait disorders are produced by pathology in one or more structures in the cortical-basal ganglia-thalamocortical\\u000a loop, which plays an important role in producing movements and postural synergies that meet personal desires and environmental\\u000a constraints. Virtually all patients with dementia have pathology in one or more components of this loop, so highest level\\u000a gait disorders are common in patients

  19. Polar Bears

    NSDL National Science Digital Library

    Mr. Thomas

    2010-09-27

    Use the following websites to answer questions about the rapid disappearance of polar bears in the Arctic region. Polar Bear picture Polar Bear Tracker 1: What region in the world has the fewest polar bears? 2: Using the internet as a resource, provide some reasons as to why this region is suffering from the most polar bear differences? Polar Bears Change Diet 1: Why are polar bears having to change their diets? 2: List some other factors (besides diet) in the ...

  20. A robot for gait rehabilitation

    E-print Network

    Roberts, Michael (Michael Henry), 1980-

    2004-01-01

    After a stroke, persons suffer from neurological impairments that affect gait, and so require rehabilitation to regain ambulatory function. While 82% of patients recover the ability to walk, current methods including ...

  1. Bearing system

    DOEpatents

    Kapich, Davorin D. (Carlsbad, CA)

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  2. The influence of gait cadence on the ground reaction forces and plantar pressures during load carriage of young adults.

    PubMed

    Castro, Marcelo P; Figueiredo, Maria Cristina; Abreu, Sofia; Sousa, Helena; Machado, Leandro; Santos, Rubim; Vilas-Boas, João Paulo

    2015-07-01

    Biomechanical gait parameters--ground reaction forces (GRFs) and plantar pressures--during load carriage of young adults were compared at a low gait cadence and a high gait cadence. Differences between load carriage and normal walking during both gait cadences were also assessed. A force plate and an in-shoe plantar pressure system were used to assess 60 adults while they were walking either normally (unloaded condition) or wearing a backpack (loaded condition) at low (70 steps per minute) and high gait cadences (120 steps per minute). GRF and plantar pressure peaks were scaled to body weight (or body weight plus backpack weight). With medium to high effect sizes we found greater anterior-posterior and vertical GRFs and greater plantar pressure peaks in the rearfoot, forefoot and hallux when the participants walked carrying a backpack at high gait cadences compared to walking at low gait cadences. Differences between loaded and unloaded conditions in both gait cadences were also observed. PMID:25766421

  3. Effects of holmium: YAG laser energy on cartilage metabolism, healing, and biochemical properties of lesional and perilesional tissue in a weight-bearing model.

    PubMed

    Pullin, J G; Collier, M A; Das, P; Smith, R L; DeBault, L E; Johnson, L L; Walls, R C

    1996-02-01

    Comparison of perilesional cartilage, lesional repair tissue, and subchondral bone activity 6 months after application of holmium-yttrium-aluminum-garnet (Ho:YAG) laser energy to chronic (10 week) induced 10-mm full-thickness (FT) circular articular cartilage craters followed by 6 months' intermittent active motion (IAM) in a free exercise environment was investigated. The 2.1-microns wavelength was delivered in hand-controlled near-contact mode by arthroscopic surgery in a saline medium. Bilateral arthroscopy was performed on normal antebrachiocarpal, intercarpal, and metacarpophalangeal joints of six adult horses. Full-thickness craters were created in nine sites per limb on weight-bearing articular surfaces with a motorized bur. Right limb craters served as sham operated controls. Animals were killed at 10 weeks after FT crater creation (n = 2), and at 24 weeks (6 months) after laser energy application (n = 4). Histological analysis using hematoxylineosin (HE) and Safranin-O staining consisted of a modified Mankin grading of perilesional cartilage and lesional repair tissue scoring. Biochemical analysis was performed for cellularity and glycosaminoglycan (GAG) synthesis. Histological analysis showed clustering of chondrocytes or perilesional zonal cloning (PZC) in 83% of laser-treated lesions and in no control lesions. No differences were observed between treated and control lesional repair activity. Laser-treated perilesional cartilage showed a significant (P < .02) decrease in GAG synthesis. No adverse effects to distant cartilage were observed after application of laser energy regarding cell proliferation or GAG synthesis. Significance of decreased GAG synthesis in treated perilesional cartilage and perilesional zonal cloning of chondrocytes in treated cartilage is unknown. Additional study of Ho:YAG laser energy application to cartilage and subchondral bone is needed before its application in the surgical management and repair of cartilage damage. PMID:8838724

  4. High frequency circular translation pin-on-disk method for accelerated wear testing of ultrahigh molecular weight polyethylene as a bearing material in total hip arthroplasty.

    PubMed

    Saikko, Vesa

    2015-01-21

    The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially increased if the circumference of the slide track is reduced in proportion, and still the wear mechanisms remain realistic and no overheating takes place. This requires an additional slow motion mechanism with which the lubrication of the contact is maintained and wear particles are conveyed away from the contact. A three-station, dual motion high frequency circular translation pin-on-disk (HF-CTPOD) device with a relative cycle frequency of 25.3 Hz and an average sliding velocity of 27.4 mm/s was designed. The pins circularly translated at high frequency (1.0 mm per cycle, 24.8 Hz, clockwise), and the disks at low frequency (31.4mm per cycle, 0.5 Hz, counter-clockwise). In a 22 million cycle (10 day) test, the wear rate of conventional gamma-sterilized UHMWPE pins against polished CoCr disks in diluted serum was 1.8 mg per 24 h, which was six times higher than that in the established 1 Hz CTPOD device. The wear mechanisms were similar. Burnishing of the pin was the predominant feature. No overheating took place. With the dual motion HF-CTPOD method, the wear testing of UHMWPE as a bearing material in total hip arthroplasty can be substantially accelerated without concerns of the validity of the wear simulation. PMID:25498368

  5. Gait analysis of spinal cord injured subjects: Effects of injury level and spasticity

    Microsoft Academic Search

    Patricia Krawetz; Patricia Nance

    1996-01-01

    Objective: To identify abnormalities in the gait of spinal cord injured (SCI) subjects, particularly in relation to injury level and spasticity.Design: Case-control study comparing the gait of SCI individuals with matched controls. Video-motion analysis was used to collect data on temporal and kinematic variables. Spasticity was assessed using the Ashworth score and pendulum test. Data regarding age, height, weight, mechanism,

  6. Synthesis of high molecular weight poly(dialkyl fumarate)s bearing n -alkyl side chains from poly(di- tert -butyl fumarate) via olefin elimination and reesterification in a one-pot

    Microsoft Academic Search

    Takayuki Otsu; Masahiro Yoshioka; Akikazu Matsumoto; Kohei Shiraishi

    1991-01-01

    High molecular weight poly(dialkyl fumarate)s bearing n-alkyl esters such as an octadecyl group were prepared efficiently from poly(di-tert-butyl fumarate) by the one-pot synthesis, i.e. both elimination of isobutene from the tert-butyl ester and the subsequent esterification were performed in a corresponding alcohol at 170–180°C in a one-pot without isolating poly(fumaric acid). The resulting polymers were characterized by IR and NMR

  7. Polar Bear Polar Bear

    NSDL National Science Digital Library

    Kelly Burgess

    2012-09-11

    In this lesson, students will listen for key details in a nonfiction text about polar bears. They will work at completing a graphic organizer with the teacher to help organize their thinking and understanding of key details about a text. They will also complete an independent assignment where they will draw or write two things that they learned about the topic.

  8. A mechanical energy analysis of gait initiation

    NASA Technical Reports Server (NTRS)

    Miller, C. A.; Verstraete, M. C.

    1999-01-01

    The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

  9. Gait Apraxia: Further Clues to Localization

    Microsoft Academic Search

    Stephen E. Nadeau

    2007-01-01

    Background\\/Aims: Gait apraxia characterized primarily by gait ignition failure has been linked to lesions involving the dorsomedial frontal lobes, but the precise locus within this general region has not been determined. It has previously been hypothesized by Thompson and Marsden that disease, disconnection, or dysfunction of supplementary motor area (SMA) may account for the similarities in the gait disorders observed

  10. Gait Stability in Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

    2013-01-01

    Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as…

  11. Association between bone stiffness and nutritional biomarkers combined with weight-bearing exercise, physical activity, and sedentary time in preadolescent children. A case-control study.

    PubMed

    Herrmann, Diana; Pohlabeln, Hermann; Gianfagna, Francesco; Konstabel, Kenn; Lissner, Lauren; Mårild, Staffan; Molnar, Dénes; Moreno, Luis A; Siani, Alfonso; Sioen, Isabelle; Veidebaum, Toomas; Ahrens, Wolfgang

    2015-09-01

    Physical activity (PA) and micronutrients such as calcium (Ca), vitamin D (25OHD), and phosphate (PO) are important determinants of skeletal development. This case-control study examined the association of these nutritional biomarkers and different PA behaviours, such as habitual PA, weight-bearing exercise (WBE) and sedentary time (SED) with bone stiffness (SI) in 1819 2-9-year-old children from the IDEFICS study (2007-2008). SI was measured on the calcaneus using quantitative ultrasound. Serum and urine Ca and PO and serum 25OHD were determined. Children's sports activities were reported by parents using a standardised questionnaire. A subsample of 1089 children had accelerometer-based PA data (counts per minute, cpm). Moderate-to-vigorous PA (MVPA) and SED were estimated. Children with poor SI (below the 15th age-/sex-/height-specific percentile) were defined as cases (N=603). Randomly selected controls (N=1216) were matched by age, sex, and country. Odds ratios (OR) for poor SI were calculated by conditional logistic regression for all biomarkers and PA behaviour variables separately and combined (expressed as tertiles and dichotomised variables, respectively). ORs were adjusted for fat-free mass, dairy product consumption, and daylight duration. We observed increased ORs for no sports (OR=1.39, p<0.05), PA levels below 524cpm (OR=1.85, p<0.05) and MVPA below 4.2% a day (OR=1.69, p<0.05) compared to WBE, high PA levels (<688cpm) and high MVPA (6.7%), respectively. SED was not associated with SI. ORs were moderately elevated for low serum Ca and 25OHD. However, biomarkers were not statistically significantly associated with SI and did not modify the association between PA behaviours and SI. Although nutritional biomarkers appear to play a minor role compared to the osteogenic effect of PA and WBE, it is noteworthy that the highest risk for poor SI was observed for no sports or low MVPA combined with lower serum Ca (<2.5mmol/l) or lower 25OHD (<43.0nmol/l). PMID:25952968

  12. Reliability of gait parameters during treadmill walking in community-dwelling healthy seniors.

    PubMed

    Faude, Oliver; Donath, Lars; Roth, Ralf; Fricker, Livia; Zahner, Lukas

    2012-07-01

    The present study aimed at assessing the between- and within-day-variability of temporal and spatial gait characteristics during treadmill walking in community-dwelling seniors. In 20 active, healthy seniors (10 women, 10 men, age: 64.8 (SD 3.2) years, height: 1.70 (0.10) m, weight: 69.7 (10.9) kg, physical activity: 11 (6) h week(-1)) gait characteristics were assessed on three days in weekly intervals (between-day variability). Either on days two or three, testing was repeated 30 min after the initial trial (within-day variability). We determined routine spatio-temporal gait parameters as well as gait variability during 400 steps at a normal walking speed (5.0 (0.4) km h(-1)) on a one-dimensional ground reaction force measuring treadmill. No significant mean differences occurred in any parameter for between- and within-day comparisons. Between-day ICC were high (ICC?0.86) for most parameters except for temporal (ICC=0.44) and spatial (ICC=0.22) gait variability. Coefficients of variation (CoV) were also high in the latter parameters (CoV=30.2-36.1%), whereas all other variables showed clearly lower values (CoV<7%). CoV were still lower between days 2 and 3 (CoV<5%). Compared to between-day comparisons, within-day variability was comparable in spatio-temporal gait parameters (CoV<5%, ICC?0.97) and lower in gait variability parameters (CoV<18%, ICC?0.72-0.74). In conclusion, most gait parameters were highly reliable during treadmill walking. Changes of less than 10% can be detected with sufficient confidence. Gait variability parameters were less reliable and, thus, should be carefully interpreted. PMID:22555061

  13. Altered Gait Termination Strategies Following a Concussion

    PubMed Central

    Buckley, Thomas A.; Munkasy, Barry A.; Tapia-Lovler, Tiffen G.; Wikstrom, Erik A.

    2013-01-01

    The purpose was to determine if planned gait termination can identify acute and lingering motor control strategy alterations in post-concussion individuals. Controls completed 2 standard gait and 5 planned gait termination trials once while concussed individuals were tested on Day-1 and Day-10 post-concussion. Dependent variables included gait velocity and normalized, relative to standard gait, peak propulsive and braking forces. Control and only Day-1 post-concussion gait velocity differed. Normalized peak propulsive and braking forces were altered on both Day-1 and Day-10. Altered propulsive and braking forces persisted despite all concussion participants achieving their baseline values on standard concussion clinical tests. Thus gait termination can detect both acute and lingering motor control strategy alterations following concussion. PMID:23489951

  14. The development of mature gait

    Microsoft Academic Search

    D Sutherland

    1997-01-01

    We must understand the natural history of immature walking in order to define and interpret pathological gait in young children. Step length, cadence and walking velocity show evidence of both central nervous system maturation and growth until approximately 4 years of age. Until 4 years-of-age the step factor (step length divided by leg length) increases, but thereafter the step factor

  15. Reflections on clinical gait analysis

    Microsoft Academic Search

    Roy B Davis

    1997-01-01

    Clinical gait analysis allows the measurement and assessment of walking biomechanics, which facilitates the identification of abnormal characteristics and the recommendation of treatment alternatives. The predominant methods for this analysis currently include the tracking of external markers placed on the patient, the monitoring of patient\\/ground interaction (e.g. ground reaction forces), and the recording of muscle electromyographic (EMG) activity, all during

  16. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. Part I. Numerical model-based optimization

    PubMed Central

    Choi, Jang-Hwan; Fahrig, Rebecca; Keil, Andreas; Besier, Thor F.; Pal, Saikat; McWalter, Emily J.; Beaupré, Gary S.; Maier, Andreas

    2013-01-01

    Purpose: Human subjects in standing positions are apt to show much more involuntary motion than in supine positions. The authors aimed to simulate a complicated realistic lower body movement using the four-dimensional (4D) digital extended cardiac-torso (XCAT) phantom. The authors also investigated fiducial marker-based motion compensation methods in two-dimensional (2D) and three-dimensional (3D) space. The level of involuntary movement-induced artifacts and image quality improvement were investigated after applying each method. Methods: An optical tracking system with eight cameras and seven retroreflective markers enabled us to track involuntary motion of the lower body of nine healthy subjects holding a squat position at 60° of flexion. The XCAT-based knee model was developed using the 4D XCAT phantom and the optical tracking data acquired at 120 Hz. The authors divided the lower body in the XCAT into six parts and applied unique affine transforms to each so that the motion (6 degrees of freedom) could be synchronized with the optical markers’ location at each time frame. The control points of the XCAT were tessellated into triangles and 248 projection images were created based on intersections of each ray and monochromatic absorption. The tracking data sets with the largest motion (Subject 2) and the smallest motion (Subject 5) among the nine data sets were used to animate the XCAT knee model. The authors defined eight skin control points well distributed around the knees as pseudo-fiducial markers which functioned as a reference in motion correction. Motion compensation was done in the following ways: (1) simple projection shifting in 2D, (2) deformable projection warping in 2D, and (3) rigid body warping in 3D. Graphics hardware accelerated filtered backprojection was implemented and combined with the three correction methods in order to speed up the simulation process. Correction fidelity was evaluated as a function of number of markers used (4–12) and marker distribution in three scenarios. Results: Average optical-based translational motion for the nine subjects was 2.14 mm (±0.69 mm) and 2.29 mm (±0.63 mm) for the right and left knee, respectively. In the representative central slices of Subject 2, the authors observed 20.30%, 18.30%, and 22.02% improvements in the structural similarity (SSIM) index with 2D shifting, 2D warping, and 3D warping, respectively. The performance of 2D warping improved as the number of markers increased up to 12 while 2D shifting and 3D warping were insensitive to the number of markers used. The minimum required number of markers for 2D shifting, 2D warping, and 3D warping was 4–6, 12, and 8, respectively. An even distribution of markers over the entire field of view provided robust performance for all three correction methods. Conclusions: The authors were able to simulate subject-specific realistic knee movement in weight-bearing positions. This study indicates that involuntary motion can seriously degrade the image quality. The proposed three methods were evaluated with the numerical knee model; 3D warping was shown to outperform the 2D methods. The methods are shown to significantly reduce motion artifacts if an appropriate marker setup is chosen. PMID:24007156

  17. Testing and Lubrication for Single Race Bearings

    SciTech Connect

    Steinhoff, R.G.

    1998-03-04

    Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.

  18. Increased treatment durations lead to greater improvements in non-weight bearing dorsiflexion range of motion for asymptomatic individuals immediately following an anteroposterior grade IV mobilisation of the talus.

    PubMed

    Holland, Christopher James; Campbell, Kevin; Hutt, Kim

    2015-08-01

    Manual therapy aims to minimise pain and restore joint mobility and function. Joint mobilisations are integral to these techniques, with anteroposterior (AP) talocrural joint mobilisations purported to increase dorsiflexion range of motion (DF-ROM). This study aimed to determine whether different treatment durations of single grade IV anteroposterior talocrural joint mobilisations elicit statistically significant differences in DF-ROM. Sixteen asymptomatic male football players (age = 27.1 ± 5.3 years) participated in the study. Non-weight bearing (NWB) and weight bearing (WB) DF-ROM was measured before and after 4 randomised treatment conditions: control treatment, 30 s, 1 min, 2 min. NWB DF-ROM was measured using a universal goniometer, and WB DF-ROM using the weight-bearing lunge test. A within-subjects design was employed so that all participants received each of the treatment conditions. A 4 × 4 balanced Latin square design and 1 week interval between sessions reduced any residual effects. Two-way repeated measures ANOVA revealed a significant improvement in DF-ROM following all AP mobilisation treatments (p < 0.001). The within subjects contrasts showed that increases in treatment duration was associated with statistically significant improvements in DF-ROM (NWB DF-ROM control = 0.01%, 30 s = 14.2%, 1 min = 21.6%, 2 min = 32.8%; WB DF-ROM control = 0.01%, 30 s = 5.0%, 1 min = 7.6%, 2 min = 10.9%; p < 0.05). However, WB DF-ROM improvements were below the minimal detectable change scores needed to conclude that improvements were not a consequence of measurement error. This research shows that single session mobilisations can elicit NWB DF-ROM improvements in asymptomatic individuals in the absence of pain, whilst increases in treatment duration confer greater improvements in NWB DF-ROM within this population. PMID:25765456

  19. Genetic feature selection for gait recognition

    NASA Astrophysics Data System (ADS)

    Tafazzoli, Faezeh; Bebis, George; Louis, Sushil; Hussain, Muhammad

    2015-01-01

    Many research studies have demonstrated that gait can serve as a useful biometric modality for human identification at a distance. Traditional gait recognition systems, however, have mostly been evaluated without explicitly considering the most relevant gait features, which might have compromised performance. We investigate the problem of selecting a subset of the most relevant gait features for improving gait recognition performance. This is achieved by discarding redundant and irrelevant gait features while preserving the most informative ones. Motivated by our previous work on feature subset selection using genetic algorithms (GAs), we propose using GAs to select an optimal subset of gait features. First, features are extracted using kernel principal component analysis (KPCA) on spatiotemporal projections of gait silhouettes. Then, GA is applied to select a subset of eigenvectors in KPCA space that best represents a subject's identity. Each gait pattern is then represented by projecting it only on the eigenvectors selected by the GA. To evaluate the effectiveness of the selected features, we have experimented with two different classifiers: k nearest-neighbor and Naïve Bayes classifier. We report considerable gait recognition performance improvements on the Georgia Tech and CASIA databases.

  20. Optimal Synchronizability of Bearings

    NASA Astrophysics Data System (ADS)

    Araújo, N. A. M.; Seybold, H.; Baram, R. M.; Herrmann, H. J.; Andrade, J. S., Jr.

    2013-02-01

    Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with asymmetrically weighted couplings. Accordingly, these networks can exhibit optimal synchronization properties through fine-tuning of the local interaction strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E 71, 016116 (2005)PLEEE81539-3755]. We show that, in analogy, the synchronizability of bearings can be maximized by counterbalancing the number of contacts and the inertia of their constituting rotor disks through the mass-radius relation, m˜r?, with an optimal exponent ?=?× which converges to unity for a large number of rotors. Under this condition, and regardless of the presence of a long-tailed distribution of disk radii composing the mechanical system, the average participation per disk is maximized and the energy dissipation rate is homogeneously distributed among elementary rotors.

  1. Totally frictionless magnetic bearing

    Microsoft Academic Search

    Wayne Dodakian; John Bulman

    2000-01-01

    A totally frictionless magnetic bearing has been developed which supports a rotor in a contactless manner. The rotor is held in a magnetic potential well via repulsive forces only. Vertical and lateral restoring forces are provided to the rotor passively via permanent magnets in such an arrangement so as to support the weight of the rotor and provide it with

  2. The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements

    PubMed Central

    Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

    2012-01-01

    Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

  3. The association between fear of falling and gait variability in both leg and trunk movements.

    PubMed

    Sawa, Ryuichi; Doi, Takehiko; Misu, Shogo; Tsutsumimoto, Kota; Nakakubo, Sho; Asai, Tsuyoshi; Yamada, Minoru; Ono, Rei

    2014-05-01

    The aim of this study was to explore whether FoF was associated with variability in both leg and trunk movements during gait in community-dwelling elderly. Ninety-three elderly people participated in this study. Each participant was categorized into either Fear or No-Fear group on the basis of having FoF. The participants walked 15m at their preferred speed. The wireless motion recording sensor units were attached to L3 spinous process and right posterior surface of heel during gait. Gait velocity, stride time and stride length were calculated. Variability in lower limb movements was represented by coefficient of variation (CV) of stride time. Trunk variability was represented by autocorrelation coefficients (AC) in three directions (vertical: VT, mediolateral: ML and anteroposterior: AP), respectively. Gait parameters were compared between groups, and further analyses were performed using generalized linear regression models after adjustment of age, sex, fall experience, height, weight, and gait velocity. Although gait velocity, mean stride time and stride length did not differ significantly between groups, stride time CV and all ACs were significantly worse in the Fear group after adjustment for variables, even including gait velocity (stride time CV: p=0.003, ?=-0.793; AC-VT: p=0.011, ?=0.053; AC-ML: p=0.044, ?=0.075; AC-AP: p=0.002, ?=0.078). Our results suggest that fear of falling is associated with variability in both leg and trunk movements during gait in community-dwelling elderly. Further studies are needed to prove a causal relationship. PMID:24656714

  4. Aerospace applications of magnetic bearings

    NASA Technical Reports Server (NTRS)

    Downer, James; Goldie, James; Gondhalekar, Vijay; Hockney, Richard

    1994-01-01

    Magnetic bearings have traditionally been considered for use in aerospace applications only where performance advantages have been the primary, if not only, consideration. Conventional wisdom has been that magnetic bearings have certain performance advantages which must be traded off against increased weight, volume, electric power consumption, and system complexity. These perceptions have hampered the use of magnetic bearings in many aerospace applications because weight, volume, and power are almost always primary considerations. This paper will review progress on several active aerospace magnetic bearings programs at SatCon Technology Corporation. The magnetic bearing programs at SatCon cover a broad spectrum of applications including: a magnetically-suspended spacecraft integrated power and attitude control system (IPACS), a magnetically-suspended momentum wheel, magnetic bearings for the gas generator rotor of a turboshaft engine, a vibration-attenuating magnetic bearing system for an airborne telescope, and magnetic bearings for the compressor of a space-rated heat pump system. The emphasis of these programs is to develop magnetic bearing technologies to the point where magnetic bearings can be truly useful, reliable, and well tested components for the aerospace community.

  5. Towards a View Invariant Gait Recognition Algorithm

    Microsoft Academic Search

    Amit A. Kale; Amit K. Roy Chowdhury; Rama Chellappa

    2003-01-01

    Human gait is a spatio-temporal phenomenon and typifies the motion characteristics of an individual. The gait of a person is easily recognizable when extracted from a side- view of the person. Accordingly, gait-recognition algo- rithms work best when presented with images where the per- son walks parallel to the camera (i.e. the image plane). However, it is not realistic to

  6. Gait Analysis and Human Motion Tracking

    Microsoft Academic Search

    Huiyu Zhou

    \\u000a We present a strategy based on human gait to achieve efficient tracking, recovery of ego-motion and 3-D reconstruction from\\u000a an image sequence acquired by a single camera attached to a pedestrian. In the first phase, the parameters of the human gait\\u000a are established by a classical frame-by-frame analysis, using an generalised least squares (GLS) technique. The gait model\\u000a is non-linear,

  7. Gait Analysis in Cervical Spondylotic Myelopathy

    PubMed Central

    Endo, Kenji; Suzuki, Hidekazu; Tanaka, Hidetoshi; Shishido, Takaaki; Yamamoto, Kengo

    2015-01-01

    Study Design Gait analysis of patients with cervical spondylotic myelopathy (CSM) by using a sheet-type gait analysis system. Purpose The aim of this study was to compare the gait patterns of patients with CSM, evaluated by the Nurick grades, and to determine the threshold values of gait parameters predicting the occurrence of a fall by using a gait recorder. Overview of Literature Gait disorder due to CSM may progress to severe paraplegia, following even a minor trauma such as a fall. The indications for the surgery of CSM without severe paralysis remain controversial. The quantitative gait analysis and the decision for decompressive surgery in patients with CSM are important in order to prevent severe paraplegia from a fall. Methods One hundred thirty-two subjects (normal, 34; CSM, 98) underwent gait analysis by using a sensor sheet. Measurements of gait cycle parameters included the step and stride length, step width, foot angle, swing phase, and stance phase. CSM was assessed by Nurick grade. Results Although the clinical symptoms were lacking, Nurick grade 1 had significant abnormalities in the parameters of velocity, step length, and step angle (p<0.05). Regarding the Nurick grade and walking phase, the length of the stance phase was increased to more than 70% of the entire walking cycle in Nurick grade 4. Conclusions Gait analysis was an objective tool for evaluating the gait stability. Our results suggested that when the percentage of the stance phase in the gait cycle increases to above 70%, the CSM patients have an increased fall risk. PMID:26097646

  8. Multi-Step Forward Dynamic Gait Simulation

    Microsoft Academic Search

    Matthew Millard; John McPhee; Eric Kubica

    A predictive forward-dynamic simulation of human gait would be extremely useful to many different researchers, and professionals.\\u000a Metabolic efficiency is one of the defining characteristics of human gait. Forward-dynamic simulations of human gait can be\\u000a used to calculate the muscle load profiles for a given walking pattern, which in turn can be used to estimate metabolic energy\\u000a consumption. One approach

  9. Performance analysis for gait in camera networks

    Microsoft Academic Search

    Michela Goffredo; Imed Bouchrika; John N. Carter; Mark S. Nixon

    2008-01-01

    ABSTRACT This paper deploys gait analysis for subject identication in multi-camera surveillance scenarios. We present a new method,for viewpoint independent markerless gait analysis that does not require camera,calibration and works with a wide range of directions of walking. These properties make the proposed method,particularly suitable for gait identi- cation in real surveillance scenarios where people and their behaviour need to

  10. Gait Analysis Laboratory

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Complete motion analysis laboratory has evolved out of analyzing walking patterns of crippled children at Stanford Children's Hospital. Data is collected by placing tiny electrical sensors over muscle groups of child's legs and inserting step-sensing switches in soles of shoes. Miniature radio transmitters send signals to receiver for continuous recording of abnormal walking pattern. Engineers are working to apply space electronics miniaturization techniques to reduce size and weight of telemetry system further as well as striving to increase signal bandwidth so analysis can be performed faster and more accurately using a mini-computer.

  11. Mechanisms of cerebellar gait ataxia

    Microsoft Academic Search

    Susanne M. Morton; Amy J. Bastian

    2007-01-01

    The cerebellum is important for movement control and plays a critical role in balance and locomotion. As such, one of the\\u000a most characteristic and sensitive signs of cerebellar damage is gait ataxia. How the cerebellum normally contributes to locomotor\\u000a behavior is unknown, though recent work suggests that it helps generate appropriate patterns of limb movements, dynamically\\u000a regulate upright posture and

  12. Gait Analysis in the Mouse

    Microsoft Academic Search

    K. A Clarke; J Still

    1999-01-01

    The gait of the adult Swiss (Mike Flack—MF1 subtype) mouse during spontaneous walk\\/trot locomotion at velocities ranging from 14–43 cm s?1 has been analysed using simultaneous video and reaction force analysis. No differences were observed between males and females. Velocity adjustments within this range are accounted for to a greater extent (>70%) by stride time decreases and to a lesser

  13. Application of the Gillette Gait Index, Gait Deviation Index and Gait Profile Score to multiple clinical pediatric populations.

    PubMed

    McMulkin, Mark L; MacWilliams, Bruce A

    2015-02-01

    Gait indices are now commonly used to assess overall pathology and outcomes from studies with instrumented gait analyses. There are differences in how these indices are calculated and therefore inherent differences in their sensitivities to detect changes or differences between groups. The purpose of the current study was to examine the three most commonly used gait indices, Gillette Gait Index (GGI), Gait Deviation Index (GDI), and Gait Profile Score (GPS), comparing the statistical sensitivity and the ability to make meaningful interpretations of the clinical results. In addition, the GDI*, a log transformed and scaled version of the GPS score which closely matches the GDI was examined. For seven previous or ongoing studies representing varying gait pathologies seen in clinical laboratories, the GGI, GDI, and GPS/GDI* were calculated retrospectively. The GDI and GPS/GDI* proved to be the most sensitive measures in assessing differences pre/post-treatment or from a control population. A power analysis revealed the GDI and GDI* to be the most sensitive statistical measures (lowest sample sizes required). Subjectively, the GDI and GDI* interpretation seemed to be the most intuitive measure for assessing clinical changes. However, the gait variable sub-scores of the GPS determined several statistical differences which were not previously noted and was the only index tool for quantifying the relative contributions of specific joints or planes of motion. The GGI did not offer any advantages over the other two indices. PMID:25623856

  14. Foil bearings

    Microsoft Academic Search

    David A. Elrod

    1993-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at

  15. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; DeMaster

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  16. Automatic Gait Optimization with Gaussian Process Regression

    Microsoft Academic Search

    Daniel J. Lizotte; Tao Wang; Michael H. Bowling; Dale Schuurmans

    2007-01-01

    Gait optimization is a basic yet challenging prob- lem for both quadrupedal and bipedal robots. Al- though techniques for automating the process ex- ist, most involve local function optimization pro- cedures that suffer from three key drawbacks. Lo- cal optimization techniques are naturally plagued by local optima, make no use of the expensive gait evaluations once a local step is

  17. Diss. ETH No 13748 WALKING GAIT CONTROL

    E-print Network

    Still, Susanna

    controllers of this type, and (ii) the demonstration of walking gait learning in a novel way using the chipDiss. ETH No 13748 WALKING GAIT CONTROL FOR FOUR-LEGGED ROBOTS Bio-inspired technology analyzed for the inter-leg coordination of four-legged walking machines. The controller is implemented using Very Large

  18. Effect of medial meniscectomy on gait parameters.

    PubMed

    Magyar, O Mátyás; Illyés, Arpád; Knoll, Zsolt; Kiss, Rita M

    2008-04-01

    The aim of this study is to determine how selected gait parameters may change as a result of medial meniscectomy at constant gait speed. Gait analysis using a ZEBRIS ultrasound based three-dimensional motion analysis system was performed in 24 patients who had undergone medial meniscectomy 18 months before the gait analysis. The constant gait speed was 3.5 km/h. Muscle activity was measured by the surface EMG system connected to the system. The muscle groups involved in the tests included (1) m. vastus medialis and (2) lateralis, (3) rectus femoris, (4) m. biceps femoris, (4) m. adductor longus, (5) m. gluteus medius, (6) m. gastrocnemius medialis and (7) lateralis. The spatial-temporal, angular parameters and intermuscular coordination determined are compared to the gait parameters of 51 healthy subjects. The study showed that medial meniscectomy resulted in a change of limb dominance; reduced knee joint motion was compensated by the increased motion of other joints in the kinematic chain-hip joint of the opposite side, pelvic obliquity-and the gait (spatial-temporal parameters) was symmetrical, with no significant differences compared to spatial-temporal parameters of healthy groups. Our study showed that the medial meniscectomy could result in adductor-free gait and reduce the rotation motion of the pelvis. PMID:17934714

  19. Safety concept for robotic gait trainers

    Microsoft Academic Search

    H. Schmidt; S. Hesse; R. Bernhardt

    2004-01-01

    The work presents a newly developed safety concept for application of robotic walking simulators based on the principle of programmable footplates in gait rehabilitation. Unlike robotic hand devices or exoskeleton robots for gait training on treadmills, which can be built relatively lightweight and require only small drives which can hardly do harm to the patient, a programmable footplate walking simulator

  20. Propulsive adaptation to changing gait speed

    Microsoft Academic Search

    Patrick O Riley; Ugo Della Croce; D Casey Kerrigan

    2001-01-01

    Understanding propulsion and adaptation to speed requirements is important in determining appropriate therapies for gait disorders. We hypothesize that adaptations for changing speed requirements occur primarily at the hip. The slow, normal and fast gait of 24 healthy young subjects was analyzed. The linear power was analyzed at the hip joint. The anterior–posterior and vertical induced accelerations of the hip

  1. Gait Analysis for Recognition and Classification

    Microsoft Academic Search

    L. Lee; W. Eric L. Grimson

    2002-01-01

    This paper describes a representation of gait appearance for the purpose of person identification and classification. This gait representation is based on simple features such as moments extracted from orthogonal view video silhouettes of human walking motion. Despite its simplicity, the re- sulting feature vector contains enough information to per- form well on human identification and gender classification tasks. We

  2. Gait Sequence Analysis Using Frieze Patterns

    Microsoft Academic Search

    Yanxi Liu; Robert T. Collins; Yanghai Tsin

    2002-01-01

    ABSTRACT We analyze walking people using a gait sequence representation that bypasses the need for frame - to - frame tracking of body parts The gait representation maps a video sequence of silhou - ettes into a pair of two - dimensional spatio - temporal patterns that are periodic along the time axis Mathematically, such patterns are called \\

  3. Gait disorders in patients with fibromyalgia

    Microsoft Academic Search

    Bernard Auvinet; Richard Bileckot; Anne-Sophie Alix; Denis Chaleil; Eric Barrey

    2006-01-01

    Objectives: The objective of this study was to compare gait in patients with fibromyalgia and in matched controls. Methods: Measurements must be obtained in patients with fibromyalgia, as the evaluation scales for this disorder are semi-quantitative. We used a patented gait analysis system (LocometrixTM Centaure Metrix, France) developed by the French National Institute for Agricultural Re- search. Relaxed walking was

  4. Gait Analysis by High School Students

    ERIC Educational Resources Information Center

    Heck, Andre; van Dongen, Caroline

    2008-01-01

    Human walking is a complicated motion. Movement scientists have developed various research methods to study gait. This article describes how a high school student collected and analysed high quality gait data in much the same way that movement scientists do, via the recording and measurement of motions with a video analysis tool and via…

  5. Fixed or mobile-bearing total knee arthroplasty

    PubMed Central

    Huang, Chun-Hsiung; Liau, Jiann-Jong; Cheng, Cheng-Kung

    2007-01-01

    Fixed and mobile-bearing in total knee arthroplasty are still discussed controversially. In this article, biomechanical and clinical aspects in both fixed and mobile-bearing designs were reviewed. In biomechanical aspect, the mobile-bearing design has proved to provide less tibiofemoral contact stresses under tibiofemoral malalignment conditions. It also provides less wear rate in in-vitro simulator test. Patients with posterior stabilized mobile-bearing knees had more axial tibiofemoral rotation than patients with posterior stabilized fixed-bearing knees during gait as well as in a deep knee-bend activity. However, in clinical aspect, the mid-term or long-term survivorship of mobile-bearing knees has no superiority over that of fixed-bearing knees. The theoretical advantages for mobile-bearing design to provide a long-term durability have not been demonstrated by any outcome studies. Finally, the fixed-bearing design with all-polyethylene tibial component is suggested for relatively inactive, elder people. The mobile-bearing design is suggested for younger or higher-demand patients due to the potential for reduced polyethylene wear and more normal kinematics response after joint replacement. For younger surgeon, the fixed-bearing design is suggested due to less demand for surgical technique. For experienced surgeon, one familiar surgical protocol and instrumentation is suggested rather than implant design, either fixed-bearing or mobile-bearing. PMID:17204165

  6. Average gait differential image based human recognition.

    PubMed

    Chen, Jinyan; Liu, Jiansheng

    2014-01-01

    The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI) is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI), AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA) is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition. PMID:24895648

  7. Gait Variability while walking with three different speeds

    Microsoft Academic Search

    Huiying Yu; Jody Riskowski; Richard Brower; T. Sarkodie-Gyan

    2009-01-01

    Gait variability is defined as changes in gait parameters from one stride to the next. Gait variability increases in individuals affected by neurodegenerative conditions such as Parkinson's disease and Huntington disease, and also with falls in the elderly and incident mobility disability. In this work, we study speed-related and age-related gait variabilities in healthy adults. Ten participants, five females (three

  8. Depth Energy Image for Gait Symmetry Quantification Caroline Rougier1

    E-print Network

    Mignotte, Max

    · Gait analysis: to help diagnostic of abnormal gait patterns · Usually with motion capture (MOCAP) [1, 2] - Problems: very expensive, complex to implement · Our gait analysis solution - Cheap depth sensor, placedDepth Energy Image for Gait Symmetry Quantification Caroline Rougier1 , Edouard Auvinet1 , Jean

  9. Gait recognition: a challenging signal processing technology for biometric identification

    Microsoft Academic Search

    N. V. Boulgouris; D. Hatzinakos; K. N. Plataniotis

    2005-01-01

    This article provides an overview of the basic research directions in the field of gait analysis and recognition. The recent developments in gait research indicate that gait technologies still need to mature and that limited practical applications should be expected in the immediate future. At present, there is a potential for initial deployment of gait for recognition in conjunction with

  10. Synchronization of oscillations for machine perception of gaits

    E-print Network

    Boyd, Jeffrey E.

    synchronized-oscillator model in various gait recognition tasks. Tools based on Procrustes analysis the model-free and model-based domains. Ó 2004 Published by Elsevier Inc. Keywords: Gait analysis; Gait recognition; Gait perception; Motion analysis; Oscillating motion; Phase- locked loops; Optical flow 1077

  11. Cyclostationary Processes on Shape Spaces for Gait-Based Recognition

    E-print Network

    Srivastava, Anuj

    . Consequently, gait analysis reduces to quantifying differences between underlying stochastic processes using profiles, and gait sequences, have been proposed for such biometric analysis. In this paper we focus of their gait. Gait analysis closely relates to statistical analysis of shapes of objects. Assuming that one

  12. Phase Models in Gait Analysis Jeffrey E. Boyd

    E-print Network

    Boyd, Jeffrey E.

    Phase Models in Gait Analysis Jeffrey E. Boyd Department of Computer Science University of Calgary­based gait analysis. The common framework allows a compari­ son of methods and suggests a path to connect­based gait anal­ ysis using a framework built upon three requirements in gait perception: frequency

  13. 3D ellipsoid fitting for multi-view gait recognition

    Microsoft Academic Search

    Sabesan Sivapalan; Daniel Chen; Simon Denman; Sridha Sridharan; Clinton Fookes

    2011-01-01

    Gait recognition approaches continue to struggle with challenges including view-invariance, low-resolution data, robustness to unconstrained environments, and fluctuating gait patterns due to subjects carrying goods or wearing different clothes. Although computationally expensive, model based techniques offer promise over appearance based techniques for these challenges as they gather gait features and interpret gait dynamics in skeleton form. In this paper, we

  14. Polar Bear

    NSDL National Science Digital Library

    2009-01-01

    In this episode of the Podcast of Life, host Ari Daniel Shapiro relates two close calls with polar bears. Listen as Heather Cray recalls how, dumped by a storm on a small Arctic island without a shotgun, she got an unexpected wake-up call. And when researcher Steve Amstrup accidentally crashed through the roof of a polar bear’s den, no one could predict what happened next. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

  15. Deficits in Scaling of Gait Force and Cycle in Parkinsonian Gait Identified by Long-Term Monitoring of Acceleration with the Portable Gait Rhythmogram

    PubMed Central

    Terashi, Hiroo; Utsumi, Hiroya; Ishimura, Yohei; Takazawa, Tomoko; Okuma, Yasuyuki; Yoneyama, Mitsuru; Mitoma, Hiroshi

    2012-01-01

    To examine the range of gait acceleration and cycle in daily walking of patients with Parkinson's disease (PD), we compared the gait of 40 patients with PD and 17 normal controls by using a newly developed long-term monitoring device that extracts gait-related accelerations from overall movements-related accelerations. The range of change in gait acceleration, relative to the control, was less than 75% in 12 patients. The range of change in gait cycle was less than 75% in 8 patients. The range of changes in both parameters was less than 75% in 4 patients. The results suggest narrow changes in gait parameters in PD. PMID:23119183

  16. Investigation of first ray mobility during gait by kinematic fluoroscopic imaging-a novel method

    PubMed Central

    2012-01-01

    Background It is often suggested that sagittal instability at the first tarso-metatarsal joint level is a primary factor for hallux valgus and that sagittal instability increases with the progression of the deformity. The assessment of the degree of vertical instability is usually made by clinical evaluation while any measurements mostly refer to a static assessment of medial ray mobility (i.e. the plantar/dorsal flexion in the sagittal plane). Testing methods currently available cannot attribute the degree of mobility to the corresponding anatomical joints making up the medial column of the foot. The aim of this study was to develop a technique which allows for a quantification of the in-vivo sagittal mobility of the joints of the medial foot column during the roll-over process under full weight bearing. Methods Mobility of first ray bones was investigated by dynamic distortion-free fluoroscopy (25 frames/s) of 14 healthy volunteers and 8 patients with manifested clinical instability of the first ray. A CAD-based evaluation method allowed the determination of mobility and relative displacements and rotations of the first ray bones within the sagittal plane during the stance phase of gait. Results Total flexion of the first ray was found to be 13.63 (SD 6.14) mm with the healthy volunteers and 13.06 (SD 8.01) mm with the patients (resolution: 0.245 mm/pixel). The dorsiflexion angle was 5.27 (SD 2.34) degrees in the healthy volunteers and increased to 5.56 (SD 3.37) degrees in the patients. Maximum rotations were found at the naviculo-cuneiform joints and least at the first tarso-metatarsal joint level in both groups. Conclusions Dynamic fluoroscopic assessment has been shown to be a valuable tool for characterisation of the kinematics of the joints of the medial foot column during gait. A significant difference in first ray flexion and angular rotation between the patients and healthy volunteers however could not be found. PMID:22316084

  17. Bobbie Bear

    NSDL National Science Digital Library

    Illuminations National Council of Teachers of Mathematics

    2009-03-06

    Using a virtual manipulative, children construct combinations of different colored shirts and pants to help Bobbie Bear, who is planning a vacation and wants to know how many different outfits he will be able to make from these combinations.

  18. Foil bearings

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1993-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  19. Gait variability and disability in multiple sclerosis.

    PubMed

    Socie, Michael J; Motl, Robert W; Pula, John H; Sandroff, Brian M; Sosnoff, Jacob J

    2013-05-01

    Gait variability is clinically relevant in some populations, but there is limited documentation of gait variability in persons with multiple sclerosis (MS). This investigation examined average and variability of spatiotemporal gait parameters in persons with MS and healthy controls and subsequent associations with disability status. 88 individuals with MS (age 52.4±11.1) and 20 healthy controls (age 50.9±8.7) performed two self-paced walking trials on a 7.9-m electronic walkway to determine gait parameters. Disability was indexed by the Expanded Disability Status Scale (EDSS) and ranged between 2.5 and 6.5. Gait variability was indexed by standard deviation (SD) and coefficient of variation (CV=SD/mean) of step time, step length, and step width. Average gait parameters were significantly correlated with EDSS (?=0.756-0.609) and were significantly different in individuals with MS compared to controls (p?0.002). Also, step length (p<0.001) and step time (p<0.001) variability were both significantly greater in MS compared to controls. EDSS was positively correlated with step length variability and individuals with MS who used assistive devices to walk had significantly greater step length variability than those who walked independently (p's<.05). EDSS was correlated with step time and length variability even when age was taken into account. Additionally, Fisher's z test of partial correlations revealed that average gait parameters were more closely related to disability status than gait variability in individuals with MS. This suggests that focusing on average gait parameters may be more important than variability in therapeutic interventions in MS. PMID:23153835

  20. Gait Speed and Survival in Older Adults

    PubMed Central

    Studenski, Stephanie; Perera, Subashan; Patel, Kushang; Rosano, Caterina; Faulkner, Kimberly; Inzitari, Marco; Brach, Jennifer; Chandler, Julie; Cawthon, Peggy; Connor, Elizabeth Barrett; Nevitt, Michael; Visser, Marjolein; Kritchevsky, Stephen; Badinelli, Stefania; Harris, Tamara; Newman, Anne B.; Cauley, Jane; Ferrucci, Luigi; Guralnik, Jack

    2011-01-01

    Context Survival estimates help individualize goals of care for geriatric patients, but life tables fail to account for the great variability in survival. Physical performance measures, such as gait speed, might help account for variability, allowing clinicians to make more individualized estimates. Objective To evaluate the relationship between gait speed and survival. Design, Setting, and Participants Pooled analysis of 9 cohort studies (collected between 1986 and 2000), using individual data from 34 485 community-dwelling older adults aged 65 years or older with baseline gait speed data, followed up for 6 to 21 years. Participants were a mean (SD) age of 73.5 (5.9) years; 59.6%, women; and 79.8%, white; and had a mean (SD) gait speed of 0.92 (0.27) m/s. Main Outcome Measures Survival rates and life expectancy. Results There were 17 528 deaths; the overall 5-year survival rate was 84.8% (confidence interval [CI], 79.6%–88.8%)and 10-year survival rate was 59.7% (95%CI, 46.5%–70.6%). Gait speed was associated with survival in all studies (pooled hazard ratio per 0.1 m/s, 0.88; 95% CI, 0.87–0.90; P<. 001). Survival increased across the full range of gait speeds, with significant increments per 0.1 m/s. At age 75, predicted 10-year survival across the range of gait speeds ranged from 19% to 87% in men and from 35% to 91% in women. Predicted survival based on age, sex, and gait speed was as accurate as predicted based on age, sex, use of mobility aids, and self-reported function or as age, sex, chronic conditions, smoking history, blood pressure, body mass index, and hospitalization. Conclusion In this pooled analysis of individual data from 9 selected cohorts, gait speed was associated with survival in older adults. PMID:21205966

  1. Innovation design of guide bearing based on TRIZ

    Microsoft Academic Search

    Zhao-hui Li; Li-jie Feng; Jin-feng Wang

    2011-01-01

    As the size and weight of the submersible motor support components increase, when bearing shell damaged, guide bearing has some disadvantages, such as, it is difficult to transport, and increases maintenance time and cost etc. To solve this problem, Triz theory is proposed in this study for innovation design of guide bearing. Firstly analyze technology system for guide bearing using

  2. Influence of backpack load and gait speed on plantar forces during walking.

    PubMed

    Watanabe, Kazuhiko; Wang, Yun

    2013-01-01

    The purpose of this study is to examine the differences in plantar force associated with changes in backpack load and gait speed during walking. The F-scan tethered system was used to collect plantar pressure data. Subjects were asked to walk on a treadmill with varied levels of backpack load (0%, 10%, 20%, and 30% of body mass) and gait speed (4, 5, and 6 km/h). We found that an increase in gait speed and backpack load lead to increase in the magnitude of the first vertical ground reaction force (vGRF) peak. Greater magnitudes of the second vGRF peak were only associated with an increase when gait speeds were 4 km/h and 5 km/h. There was no speed-related change in the magnitudes of the second vGRF peak at the speed of 6 km/h. The results of this study may be important for the purpose of constituting a load-bearing walking program for protecting against osteoporosis. PMID:24067124

  3. SURGICAL CORRECTION OF BILATERAL PATELLAR LUXATION IN AN AMERICAN BLACK BEAR CUB (URSUS AMERICANUS).

    PubMed

    Bennett, Katarina R; Desmarchelier, Marion R; Bailey, Trina R

    2015-06-01

    A wild orphaned male American black bear cub ( Ursus americanus ) presented with hind limb gait abnormalities and was found to have bilateral grade 3 laterally luxating patellas. There were no other significant abnormalities detected on neurologic, radiographic, or hematologic examinations. The trochlear grooves were deepened with a chondroplasty, and the redundant soft tissues imbricated. There was a marked improvement in the bear's gait postoperatively, with an apparent full return to function. To the authors' knowledge, patellar luxation has not been reported in the Ursidae family, and the success in this case suggests that this technique may be used in large wild or captive carnivore cubs. PMID:26056894

  4. Gait recognition based on Gabor wavelets and modified gait energy image for human identification

    NASA Astrophysics Data System (ADS)

    Huang, Deng-Yuan; Lin, Ta-Wei; Hu, Wu-Chih; Cheng, Chih-Hsiang

    2013-10-01

    This paper proposes a method for recognizing human identity using gait features based on Gabor wavelets and modified gait energy images (GEIs). Identity recognition by gait generally involves gait representation, extraction, and classification. In this work, a modified GEI convolved with an ensemble of Gabor wavelets is proposed as a gait feature. Principal component analysis is then used to project the Gabor-wavelet-based gait features into a lower-dimension feature space for subsequent classification. Finally, support vector machine classifiers based on a radial basis function kernel are trained and utilized to recognize human identity. The major contributions of this paper are as follows: (1) the consideration of the shadow effect to yield a more complete segmentation of gait silhouettes; (2) the utilization of motion estimation to track people when walkers overlap; and (3) the derivation of modified GEIs to extract more useful gait information. Extensive performance evaluation shows a great improvement of recognition accuracy due to the use of shadow removal, motion estimation, and gait representation using the modified GEIs and Gabor wavelets.

  5. Improved Superconducting Magnetic Rotary Bearings

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Royston, James

    1992-01-01

    Improved magnetic rotary bearings designed by exploiting properties of type-II superconducting materials. Depending on design and application, bearing provides fixed or adjustable compensation for lateral vector component of weight or other lateral load on rotor. Allows applied magnetic field to penetrate partially in clusters of field lines, with concomitant establishment of undamped circulating electrical currents within material. Type-II superconductors have critical magnetic fields and critical temperatures greater than type-I superconductors.

  6. Gait training facilitates central drive to ankle dorsiflexors in children with cerebral palsy.

    PubMed

    Willerslev-Olsen, Maria; Petersen, Tue Hvass; Farmer, Simon Francis; Nielsen, Jens Bo

    2015-03-01

    Foot drop and toe walking are frequent concerns in children with cerebral palsy. The main underlying cause of these problems is early damage and lack of maturation of the corticospinal tract. In the present study we investigated whether 4 weeks of daily treadmill training with an incline may facilitate corticospinal transmission and improve the control of the ankle joint in children with cerebral palsy. Sixteen children with cerebral palsy (Gross Motor Classification System I:6, II:6, III:4) aged 5-14 years old, were recruited for the study. Evaluation of gait ability and intramuscular coherence was made twice before and twice after training with an interval of 1 month. Gait kinematics were recorded by 3D video analysis during treadmill walking with a velocity chosen by the child at the first evaluation. Foot pressure was measured by force sensitive foot soles during treadmill and over ground walking. EMG-EMG coherence was calculated from two separate electrode recordings placed over the tibialis anterior muscle. Training involved 30 min of walking daily on a treadmill with an incline for 30 days. Gait training was accompanied by significant increases in gait speed, incline on the treadmill, the maximal voluntary dorsiflexion torque, the number and amplitude of toe lifts late in the swing phase during gait and the weight exerted on the heel during the early stance phase of the gait cycle. EMG-EMG coherence in the beta and gamma frequency bands recorded from tibialis anterior muscle increased significantly when compared to coherence before training. The largest changes in coherence with training were observed for children <10 years of age. Importantly, in contrast to training-induced EMG increases, the increase in coherence was maintained at the follow-up measurement 1 month after training. Changes in the strength of coherence in the beta and gamma band were positively correlated with improvements in the subjects' ability to lift the toes in the swing phase. These data show that daily intensive gait training increases beta and gamma oscillatory drive to ankle dorsiflexor motor neurons and that it improves toe lift and heel strike in children with cerebral palsy. We propose that intensive gait training may produce plastic changes in the corticospinal tract, which are responsible for improvements in gait function. PMID:25623137

  7. Gait quality is improved by locomotor training in individuals with SCI regardless of training approach

    PubMed Central

    Nooijen, Carla FJ; ter Hoeve, Nienke; Field-Fote, Edelle C

    2009-01-01

    Background While various body weight supported locomotor training (BWSLT) approaches are reported in the literature for individuals with spinal cord injury (SCI), none have evaluated outcomes in terms of gait quality. The purpose of this study was to compare changes in measures of gait quality associated with four different BWSLT approaches in individuals with chronic motor-incomplete SCI, and to identify how gait parameters differed from those of non-disabled (ND) individuals. Methods Data were analyzed from 51 subjects with SCI who had been randomized into one of four BWSLT groups: treadmill with manual assistance (TM), treadmill with electrical stimulation (TS), overground with electrical stimulation (OG), treadmill with locomotor robot (LR). Subjects with SCI performed a 10-meter kinematic walk test before and after 12 weeks of training. Ten ND subjects performed the test under three conditions: walking at preferred speed, at speed comparable to subjects with SCI, and with a walker at comparable speed. Six kinematic gait quality parameters were calculated including: cadence, step length, stride length, symmetry index, intralimb coordination, and timing of knee extension. Results In subjects with SCI, all training approaches were associated with improvements in gait quality. After training, subjects with SCI walked at higher cadence and had longer step and stride lengths. No significant differences were found among training groups, however there was an interaction effect indicating that step and stride length improved least in the LR group. Compared to when walking at preferred speed, gait quality of ND subjects was significantly different when walking at speeds comparable to those of the subjects with SCI (both with and without a walker). Post training, gait quality measures of subjects with SCI were more similar to those of ND subjects. Conclusion BWSLT leads to improvements in gait quality (values closer to ND subjects) regardless of training approach. We hypothesize that the smaller changes in the LR group were due to the passive settings used for the robotic device. Compared to walking at preferred speed, gait quality values of ND individuals walking at a slower speed and while using a walker were more similar to those of individuals with SCI. PMID:19799783

  8. Cave Bear

    NSDL National Science Digital Library

    American Association for the Advancement of Science (; )

    2005-08-15

    Decoding an ancient cave bear. A two-ton, thirteen-foot cave bear, extinct for ten thousand years, has just experienced a rebirth of sorts. From a tooth and a bone, scientists have recovered its entire genetic code.Eddy Rubin, director of the Department of Energy's Joint Genome Institute, says finding genuine cave bear DNA was like looking for a needle in a haystack. The haystack were all the other organisms that were living in the bones and in the tooth of this ancient creature. And the needle was the little bit of the ancient creature's genome DNA, or genes.They used state-of-the-art computer technology to separate the bear genes from the clutter. Jurassic Park fans should note that they can't clone a new cave bear, nor can they recover DNA from creatures as old as the dinosaurs. But they do hope to reconstruct the genetic code of Neanderthals, our closest non-human relatives, to better understand how our own species evolved. This resource contains detailed text description of the research as well as likes for further inquiry.

  9. Design of a robot for gait rehabilitation

    E-print Network

    Bosecker, Caitlyn Joyce

    2009-01-01

    The ability to walk is important for independent living and when this capacity is affected by injury, gait therapy is the traditional approach to re-train the nervous system, to re-build muscle strength, to improve balance, ...

  10. Perception Based Gait Generation for Quadrupedal Characters 

    E-print Network

    Zhou, Junze

    2013-04-30

    -controlled tools and modifiers to build creature shape and synthesize cyclic gait animation. This new approach accomplished the goal of quick generation of expressive characters. It is also successful in achieving real-time animation playback and adjustment....

  11. Gait termination: a review of experimental methods and the effects of ageing and gait pathologies.

    PubMed

    Sparrow, W A; Tirosh, Oren

    2005-12-01

    The study of human gait has expanded and diversified to the extent that it is now possible to identify a substantive literature concerning a variety of gait tasks, such as gait initiation [Halliday SE, Winter DA, Frank JS, Patla AE, Prince F. The initiation of gait in young, elderly, and Parkinson's disease subjects. Gait Posture 1998;8:8-14; Mickelborough J, van der Linden ML, Tallis RC, Ennos AR. Muscle activity during gait initiation in normal elderly people. Gait Posture 2004;19:50-57], stepping over and across obstacles [Patla AE, Prentice SD, Robinson C, Newfold J. Visual control of locomotion: strategies for changing direction and for going over obstacles. J Exp Psych 1991;17:603-34; Chen, HC, Ashton-Miller JA, Alexander NB, Schultz AB. Effect of age and available response time on ability to step over an obstacle. J Gerontol 1994;49:227-33; Sparrow WA, Shinkfield AJ, Chow S, Begg RK. Gait characteristics in stepping over obstacles. Hum Mov Sci 1996;15:605-22; Begg RK, Sparrow WA, Lythgo ND. Time-domain analysis of foot-ground reaction forces in negotiating obstacles. Gait Posture 1998;7:99-109; Patla AE, Rietdyk S. Visual control of limb trajectory over obstacles during locomotion: effect of obstacle height and width. Gait Posture 1993;1:45-60] negotiating raised surfaces such as curbs and stairs [Begg RK, Sparrow WA. Gait characteristics of young and older individuals negotiating a raised surface: implications for the prevention of falls. J Gerontol Med Sci 2000;55A:147-54; Mcfayden BJ, Winter DA. An integrated biomechanical analysis of normal stair ascent and descent. J Biomech 1988;21:733-44]. In addition, increasing research interest in age-related declines in gait that might predispose individuals to falls has engendered a very extensive literature concerning ageing effects on gait. While rapid locomotor adjustments are common in the course of daily activities there has been no previous review of the findings concerning gait adaptations when walking is terminated both rapidly and unexpectedly. The aims of this review were first, to summarise the key research findings and methodological considerations from studies of termination. The second aim was to demonstrate the effects of ageing and gait pathologies on termination with respect to the regulation of step characteristics, lower-limb muscle activation patterns and foot-ground reaction forces. PMID:16274920

  12. Effects of Spaceflight and Hindlimb Suspension on the Posture and Gait of Rats

    NASA Technical Reports Server (NTRS)

    Fox, R. A.; Corcoran, M.; Daunton, N. G.; Morey-Holton, E.

    1994-01-01

    Instability of posture and gait in astronauts following spaceflight (SF) is thought to result from muscle atrophy and from changes in sensory-motor integration in the CNS (central nervous system) that occur during adaptation to microgravity (micro-G). Individuals are thought to have developed, during SF, adaptive changes for the processing of proprioceptive, vestibular and visual sensory inputs with reduced weighting of gravity-based signals and increased weighting of visual and tactile cues. This sensory-motor rearrangement in the CNS apparently occurs to optimize neuromuscular system function for effective movement and postural control in micro-G. However, these adaptive changes are inappropriate for the 1 g environment and lead to disruptions in posture and gait on return to Earth. Few reports are available on the effects of SF on the motor behavior of animals. Rats studied following 18.5 - 19.5 days of SF in the COSMOS program were described as being ..'inert, apathetic, slow'.. and generally unstable. The hindlimbs of these rats were ..'thrust out from the body with fingers pulled apart and the shin unnaturally pronated'. On the 6th postflight day motor behavior was described as similar to that observed in preflight observations. Improved understanding of the mechanisms leading to these changes can be obtained in animal models through detailed analysis of neural and molecular mechanisms related to gait. To begin this process the posture and gait of rats were examined following exposure to either SF or hindlimb suspension (HLS), and during recovery from these conditions.

  13. Effect of backpack load on the head, cervical spine and shoulder postures in children during gait termination.

    PubMed

    Mo, Shi Wei; Xu, Dong-Qing; Li, Jing Xian; Liu, Meng

    2013-01-01

    Twelve boys with an average age of 9.9 years were instructed to carry backpacks that weighed 0%, 10% and 15% of their body weights (BWs) to complete planned and unplanned gait termination experiments. The craniohorizontal, craniovertebral and sagittal shoulder posture angles at the sagittal plane as well as the anterior head alignment and coronal shoulder posture angles at the coronal plane were analysed. Results revealed significantly smaller craniohorizontal and sagittal shoulder posture angles during planned gait termination and a significantly smaller sagittal shoulder posture angle during unplanned gait termination under loaded conditions compared with those at 0% BW backpacks. Furthermore, the coronal shoulder posture angles at 10% and 15% BW during planned and unplanned gait terminations were significantly larger than those at 0% BW. Therefore, subjects were more likely to have a forward head posture, rounded shoulder posture and increased lateral tilting of the shoulders during gait termination as backpack loads were increased. However, gait termination, whether planned or unplanned, did not elicit a remarkable effect on posture. PMID:24206277

  14. Gait dynamics in Parkinson's disease: Common and distinct behavior among stride length, gait variability, and fractal-like scaling

    NASA Astrophysics Data System (ADS)

    Hausdorff, Jeffrey M.

    2009-06-01

    Parkinson's disease (PD) is a common, debilitating neurodegenerative disease. Gait disturbances are a frequent cause of disability and impairment for patients with PD. This article provides a brief introduction to PD and describes the gait changes typically seen in patients with this disease. A major focus of this report is an update on the study of the fractal properties of gait in PD, the relationship between this feature of gait and stride length and gait variability, and the effects of different experimental conditions on these three gait properties. Implications of these findings are also briefly described. This update highlights the idea that while stride length, gait variability, and fractal scaling of gait are all impaired in PD, distinct mechanisms likely contribute to and are responsible for the regulation of these disparate gait properties.

  15. 19 CFR 10.98 - Copper-bearing fluxing material.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

  16. 19 CFR 10.98 - Copper-bearing fluxing material.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

  17. 19 CFR 10.98 - Copper-bearing fluxing material.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

  18. 19 CFR 10.98 - Copper-bearing fluxing material.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

  19. 19 CFR 10.98 - Copper-bearing fluxing material.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

  20. Lack of maintenance of gait pattern as measured by instrumental methods suggests psychogenic gait

    PubMed Central

    Merello, Marcelo; Ballesteros, Diego; Rossi, Malco; Arena, Julieta; Crespo, Marcos; Cervio, Andres; Oderiz, Carolina Cuello; Rivero, Alberto; Cerquetti, Daniel; Risk, Marcelo; Balej, Jorge

    2012-01-01

    Summary Fluctuation is a common feature of all psychogenic gait disorder (PGD) patterns. Whether this fluctuation involves only the degree of impairment or whether it affects the gait pattern itself remains an interesting question. We hypothesize that, on repeated measurements, both normal and abnormal gait may present quantitative differences while maintaining their basic underlying pattern; conversely, in psychogenic gait, the basic pattern appears not to be preserved. Using an optoelectronic system, data acquired from 19 normal subjects and 66 patients were applied to train a neural network (NN) and subsequently classify gait patterns into four different groups (normal, ataxic, spastic-paraparetic and parkinsonian). Five patients who fulfilled clinical criteria for psychogenic gait and six controls were then prospectively evaluated on two separate occasions, three months apart. Normal controls and ataxic, parkinsonian or spastic patients were correctly identified by the NN, and categorized within the corresponding groups at baseline as well as at a three-month follow-up evaluation. NN analysis showed that after three months, no PGD patient preserved the gait pattern detected at baseline, even though this finding was not clinically apparent. Modification of gait pattern detected by repeated kinematic measurement and NN analysis could suggest the presence of PGD, particularly in difficult-to-diagnose cases. PMID:23597435

  1. Bear Bones

    NSDL National Science Digital Library

    Science Update

    2004-03-08

    An estimated ten million Americans have osteoporosis, an age-related disease in which the bones gradually become brittle and weak. Now, scientists are looking to animals for clues on how to combat this condition. This resource describes the study of sustaining bone strength of hibernating bears.

  2. System for testing bearings

    NASA Technical Reports Server (NTRS)

    Gibson, John C. (inventor)

    1993-01-01

    Disclosed here is a system for testing bearings wherein a pair of spaced bearings provides support for a shaft on which is mounted a bearing to be tested, this bearing being mounted in a bearing holder spaced from and in alignment with the pair of bearings. The bearing holder is provided with an annular collar positioned in an opening in the bearing holder for holding the bearing to be tested. A screw threaded through the bearing holder into engagement with the annular collar can be turned to force the collar radially out of alignment with the pair of bearings to apply a radial load to the bearing.

  3. The role of excess mass in the adaptation of children's gait.

    PubMed

    Shultz, Sarah P; D'Hondt, Eva; Lenoir, Matthieu; Fink, Philip W; Hills, Andrew P

    2014-08-01

    The aim of this study was to determine differences in lower extremity joint powers at weight acceptance and propulsion in obese and non-obese children during two loading conditions. Gait analyses were conducted on 20 non-obese and 20 obese children (8-12years). The first testing session was completed in a normal (unloaded) condition; an additional 10% body mass (acute loading) was added during the second session. Peak lower extremity joint power (W) phases were identified at weight acceptance and propulsion. Obese children demonstrated greater joint powers than non-obese children, at both weight acceptance and propulsion. Likewise, all children produced larger joint powers during acute loading conditions than unloaded. When body mass is a covariate, significant main effects for loading conditions remained for the hip and knee during weight acceptance and the hip and ankle at propulsion; no group differences remained significant. Obese children produced greater power generation at the hip and ankle during unloaded conditions than non-obese children during acute conditions. Only the ankle had greater power generation after accounting for body mass. The findings suggest that obese children must increase muscular contraction force to maintain normal gait function. While increased joint powers necessary for normal gait could result in incidental muscle strengthening of obese children, this persistent increase in muscular force demand could result in musculoskeletal injury. PMID:24908185

  4. Virtual walkway system and prediction of gait mode transition for the control of the gait simulator.

    PubMed

    Shiozawa, N; Arima, S; Makikawa, M

    2004-01-01

    A virtual walkway system is proposed in This work. This system consists of a new developed gait simulator and a HMD system to present virtual space to the user. The gait simulator is designed to permit the user to walk straight, change direction, go up and down stairs, etc. Main part of this gait simulator is two foot plates driven by three arms and actuators. Each foot plate follows the foot during swing phase and pulls it back during the stance phase while the user is walking straight However this gait simulator has one weak point, that is, this simulator cannot follow the change of gait mode sufficiently, like the start of walking or the end of walking. To solve this problem it is necessary to predict the change of gait mode to follow the transition perfectly. In this paper we chose the start and the end of straight walking and have tried to measure this transition of gait mode. To do this we paid attention on the anterior bending of the upper trunk. It is expected that the trunk bends forward before the start of walking and bends back before the stop of walking. In the experiment the distance between the upper trunk and the center of gravity (COG) was measured and it was proven that the measurement of this distance showed to be useful to know the transition of straight walking. This result was examined again on the gait simulator. Implanted control algorithm of gait simulator is as follows; two foot plates pull back the feet when the start of walking was predicted and stop when the stop of walking was predicted. Results show that the gait simulator was able to reproduce the start and the end of walking by this prediction algorithm. PMID:17270833

  5. Gait Initiation in Children with Rett Syndrome

    PubMed Central

    Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L.; Frigo, Carlo Albino; Cavallari, Paolo

    2014-01-01

    Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait. PMID:24743294

  6. Advancing clinical gait analysis through technology and policy

    E-print Network

    Tan, Junjay

    2009-01-01

    Quantitatively analyzing human gait biomechanics will improve our ability to diagnose and treat disability and to measure the effectiveness of assistive devices. Gait analysis is one technology used to analyze walking, but ...

  7. Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation

    E-print Network

    Kang, Kyungdae

    2011-02-22

    An objective in the design of high performance machinery is to minimize weight so magnetic bearings are often designed to operate slightly lower than the magnetic material saturation. Further weight reduction in the bearings requires operation...

  8. MFC histogram and Poincare plot images for automated gait detection

    Microsoft Academic Search

    R. Begg; M. Palaniswami; B. Owen; S. Taylor; L. Dell'Oro

    2004-01-01

    In this paper, we apply support vector machines (SVMs) for the automatic recognition of young-old gait from their respective gait-patterns. Minimum foot clearance (MFC) data of 30 young and 28 elderly participants were analysed using a PEAK-2D motion analysis system. Gait features extracted from individual MFC histogram-plot and Poincare-plots were used to develop gait classification models using SVMs. Test results

  9. Gait synchronization in Caenorhabditis elegans

    PubMed Central

    Yuan, Jinzhou; Raizen, David M.; Bau, Haim H.

    2014-01-01

    Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

  10. The asymmetric gait toenail unit sign.

    PubMed

    Zaias, Nardo; Rebell, Gerbert; Casal, German; Appel, Jason

    2012-01-01

    The aim of this investigation was to resolve a diagnostic problem and report toenail unit changes attributable to shoe friction that resemble onychomycosis, but that are fungus-negative, and identify common skeletal causes in patients with an asymmetric walking gait. X-ray and clinical feet inspections were performed to evaluate skeletal components that change normal foot biodynamics. Forty-nine patients, all dermatophyte-negative, were reviewed. All patients were those seen in our private practice who demonstrated skeletal and toenail unit abnormalities such as onycholysis, nail bed keratosis resembling distal subungual onychomycosis, nail plate surface abnormalities, distal toe skin keratosis, a diagnostic nail plate shape, as well as several skeletal abnormalities. The clinical abnormalities of the asymmetric gait syndrome include onycholysis, nail bed keratosis, nail plate surface abnormalities, and a diagnostic nail plate shape. By the patient's history, the skeletal findings that were present worsened with age and, in many patients, they were familial. Onychomycosis does not lead to an asymmetric gait nail problem, asymmetric gait toenail does not favor dermatophyte infection, and not all nail dystrophies are the result of an asymmetric walking gait. PMID:23008938

  11. Gait stability in children with cerebral palsy

    PubMed Central

    Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

    2013-01-01

    Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE’s sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (~1.5 cm), while effects of walking speed (~20 cm per m/s increase in walking speed) and group (~5cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP. PMID:23500163

  12. Human odometer is gait-symmetry specific.

    PubMed

    Turvey, Michael T; Romaniak-Gross, Carissa; Isenhower, Robert W; Arzamarski, Ryan; Harrison, Steven; Carello, Claudia

    2009-12-22

    In 1709, Berkeley hypothesized of the human that distance is measurable by 'the motion of his body, which is perceivable by touch'. To be sufficiently general and reliable, Berkeley's hypothesis must imply that distance measured by legged locomotion approximates actual distance, with the measure invariant to gait, speed and number of steps. We studied blindfolded human participants in a task in which they travelled by legged locomotion from a fixed starting point A to a variable terminus B, and then reproduced, by legged locomotion from B, the A-B distance. The outbound ('measure') and return ('report') gait could be the same or different, with similar or dissimilar step sizes and step frequencies. In five experiments we manipulated bipedal gait according to the primary versus secondary distinction revealed in symmetry group analyses of locomotion patterns. Berkeley's hypothesis held only when the measure and report gaits were of the same symmetry class, indicating that idiothetic distance measurement is gait-symmetry specific. Results suggest that human odometry (and perhaps animal odometry more generally) entails variables that encompass the limbs in coordination, such as global phase, and not variables at the level of the single limb, such as step length and step number, as traditionally assumed. PMID:19740881

  13. Gait characteristics in individuals with intellectual disabilities: a literature review.

    PubMed

    Almuhtaseb, Sanaa; Oppewal, Alyt; Hilgenkamp, Thessa I M

    2014-11-01

    Gait is a functionally highly relevant aspect of motor performance. In the general population poorer gait increases the risk of falls and is a predictor for future disability, cognitive impairment, institutionalization and/or mortality. People with intellectual disabilities (ID) show a delayed motor development, which brings to attention the abnormalities that might accompany gait in this population throughout childhood and adulthood. Therefore, this paper aims (a) to provide a focused review of the available literature on gait characteristics in individuals with ID and (b) to gain insight into available instrumentations measuring gait in this population. We searched the database of PubMed for relevant articles and the reference lists of included articles, resulting in 44 included articles. Forty one studies reported gait characteristics during over-ground walking and six studies during perturbed walking conditions. Most studies investigated syndrome-specific ID populations, only five studies investigated the general ID population. The studies show that gait abnormalities are evident during over-ground walking in the ID population, both in people with genetic syndromes and with ID without genetic syndromes. During perturbed conditions people with ID altered their gait with stability-enhancing adaptations. Abnormalities in gait may be partly explained by physical features, but the interrelatedness between gait and cognition may also be an explanation for the gait abnormalities seen in the ID population. Further research regarding gait characteristics of the ID population, and its relation to cognitive functioning, and adverse health outcomes is needed. PMID:25105568

  14. Efficient tracking and ego-motion recovery using gait analysis

    Microsoft Academic Search

    Huiyu Zhou; Andrew M. Wallace; Patrick R. Green

    2009-01-01

    We present a strategy based on human gait to achieve efficient tracking, recovery of ego- motion and 3-D reconstruction from an image sequence acquired by a single camera attached to a pedestrian. In the first phase, the parameters of the human gait are established by a classical frame-by-frame analysis, using an generalized least squares (GLS) technique. The gait model is

  15. Influence of cell phone email use on characteristics of gait

    Microsoft Academic Search

    Shinichi Demura; Masanobu Uchiyama

    2009-01-01

    Previously, gait had been considered an automatic and rhythmical movement that uses minimal attentional resources. The relationship between attention and gait has been revealed in recent research. However, in young adults in particular, the influence of using a cell phone – which is used frequently in daily life and considered to require high attentional demands – on gait has not

  16. Self-Calibrating View-Invariant Gait Biometrics

    Microsoft Academic Search

    Michela Goffredo; Imed Bouchrika; John N. Carter; Mark S. Nixon

    2009-01-01

    We present a new method for viewpoint independent gait biometrics. The system relies on a single camera, does not require camera calibration, and works with a wide range of camera views. This is achieved by a formulation where the gait is self-calibrating. These properties make the proposed method par- ticularly suitable for identification by gait, where the advantages of completely

  17. Self-Calibrating View-Invariant Gait Biometrics

    Microsoft Academic Search

    Michela Goffredo; Imed Bouchrika; John N. Carter; Mark S. Nixon

    2010-01-01

    We present a new method for viewpoint independent gait biometrics. The system relies on a single camera, does not require camera calibration, and works with a wide range of camera views. This is achieved by a formulation where the gait is self-calibrating. These properties make the proposed method particularly suitable for identification by gait, where the advantages of completely unobtrusiveness,

  18. QUADRUPED OPTIMUM GAITS ANALYSIS FOR PLANETARY EXPLORATION Ioannis Kontolatis (1)

    E-print Network

    Papadopoulos, Evangelos

    QUADRUPED OPTIMUM GAITS ANALYSIS FOR PLANETARY EXPLORATION Ioannis Kontolatis (1) , Dimitrios on the performance and gait characteristics of a quadruped robot. This paper presents results obtained using a planar quadruped robot gaits. In addition, an optimization procedure using either MathWorks fmincon

  19. Kinetics of stiff-legged gait: induced acceleration analysis

    Microsoft Academic Search

    Patrick O. Riley; D. Casey Kerrigan

    1999-01-01

    Treating spastic paretic stiff-legged gait, defined as reduced knee flexion in swing, holds a high priority in the rehabilitation of patients with upper motor neuron lesions. We propose a method to determine the relative contributions of hip, knee, and ankle inpairments to this disability. We analyzed the gait of ten patients with stiff-legged gait (SLG) due to a single stroke

  20. Biomechanical analysis of gait adaptation in the nematode Caenorhabditis elegans

    E-print Network

    Biomechanical analysis of gait adaptation in the nematode Caenorhabditis elegans Christopher Fang to adapt its locomotory gait to its physical surroundings. The nema- tode Caenorhabditis elegans, between swimming in water and crawling on surfaces, adapts its locomotory gait to surroundings that impose

  1. The evolution of clinical gait analysis part l: kinesiological EMG

    Microsoft Academic Search

    David H. Sutherland

    2001-01-01

    Abstract In 1996, I was asked by Roy Davis, President of the Gait and Clinical Movement Analysis Society, to be the presidential guest speaker at the Birmingham, AL, annual society meeting and present a talk on the development of clinical gait analysis. Following my presentation, James Gage, Editor-in-Chief for Gait and Posture, and David Winter, Associate Editor for review articles

  2. Using Causal Reasoning in Gait Analysis 1 David E. Hirsch *

    E-print Network

    Szolovits, Peter

    Using Causal Reasoning in Gait Analysis 1 David E. Hirsch * Department of Electrical Engineering in gait analysis. Applied Artificial Intelligence, 3(2­3):337­356, 1989. The final version is not available on­line. #12; DRAFT May 12, 1995 page 1 Using Causal Reasoning in Gait Analysis David E. Hirsch

  3. Human Odometry Verifies the Symmetry Perspective on Bipedal Gaits

    ERIC Educational Resources Information Center

    Turvey, M. T.; Harrison, Steven J.; Frank, Till D.; Carello, Claudia

    2012-01-01

    Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias "cells") required to model them. Primary gaits are characterized by dihedral symmetry, whereas secondary gaits are characterized by a lower, cyclic symmetry. This fact was used in a test of human odometry. Results…

  4. Coupled Nonlinear Oscillators and the Symmetries of Animal Gaits

    Microsoft Academic Search

    J. J. Collins; I. N. Stewart

    1993-01-01

    Summary. Animal locomotion typically employs several distinct periodic patterns of leg movements, known as gaits. It has long been observed that most gaits possess a degree of symmetry. Our aim is to draw attention to some remarkable parallels between the generalities of coupled nonlinear oscillators and the observed symmetries of gaits, and to describe how this observation might impose constraints

  5. The relationship between 2D static features and 2D dynamic features used in gait recognition

    NASA Astrophysics Data System (ADS)

    Alawar, Hamad M.; Ugail, Hassan; Kamala, Mumtaz; Connah, David

    2013-05-01

    In most gait recognition techniques, both static and dynamic features are used to define a subject's gait signature. In this study, the existence of a relationship between static and dynamic features was investigated. The correlation coefficient was used to analyse the relationship between the features extracted from the "University of Bradford Multi-Modal Gait Database". This study includes two dimensional dynamic and static features from 19 subjects. The dynamic features were compromised of Phase-Weighted Magnitudes driven by a Fourier Transform of the temporal rotational data of a subject's joints (knee, thigh, shoulder, and elbow). The results concluded that there are eleven pairs of features that are considered significantly correlated with (p<0.05). This result indicates the existence of a statistical relationship between static and dynamics features, which challenges the results of several similar studies. These results bare great potential for further research into the area, and would potentially contribute to the creation of a gait signature using latent data.

  6. MRI of Weight-bearing and Movement

    PubMed Central

    Shapiro, Lauren M.; Gold, Garry E.

    2011-01-01

    Conventional, static magnetic resonance imaging (MRI) is able to provide a vast amount of information regarding the anatomy and pathology of the musculoskeletal system. However, patients, especially those whose pain is position dependent or elucidated by movement, may benefit from more advanced imaging techniques that allow for the acquisition of functional information. This manuscript reviews a variety of advancements in magnetic resonance imaging techniques that are used to image the musculoskeletal system dynamically, while in motion or under load. The methodologies, advantages and drawbacks of Stress MRI, Cine PC MRI and Real-Time MRI are discussed as each has helped to advance the field by providing a scientific basis for understanding normal and pathological musculoskeletal anatomy and function. Advancements in dynamic MR imaging will certainly lead to improvements in the understanding, prevention, diagnosis and treatment of musculoskeletal disorders. It is difficult to anticipate that dynamic MRI will replace conventional MRI, however, dynamic MRI may provide additional valuable information to findings of conventional MRI. PMID:22138286

  7. Gait in stroke: assessment and rehabilitation.

    PubMed

    Richards, C L; Malouin, F; Dean, C

    1999-11-01

    This article discusses the assessment and treatment of gait disorders after stroke. After consideration of the effects (of the disturbed motor control resulting from stroke) on the gait movements and the expected rate of recovery of walking capacity, different methods of assessment are considered. Emphasis is placed on selecting the appropriate measurement tool according to the individual's level of function. Also, the need to measure walking performance under different environmental constraints and the importance of instrument responsiveness to change over the range of walking disabilities are discussed. Task-related training with the opportunity for large amounts of practice is recommended to improve walking performance after stroke. PMID:10499938

  8. Analysis of Human Gait Radar Signal Using Reassigned WVD

    NASA Astrophysics Data System (ADS)

    Zhang, Jun

    Human gait is one of the biological features for human recognition. The key feature of gait can be acquired by analyzing the human echo signal to CW radar. Based on the data from the test CW gait radar, the methods for analyzing multi-component non-stationary signal are discussed in detail. The comparison among the application STFT, WVD, Pseudo-smoothed WVD and its improvements in gait signal are given, and the basic method for gait feature extraction based on time-frequency analysis is proposed. The results in this paper will be a well support for further research.

  9. Treadmill training with partial body weight support after stroke: a review.

    PubMed

    Hesse, Stefan

    2008-01-01

    Restoration and improvement of gait after stroke are major aspects of neurorehabilitation. Mobilization out of the bed into the wheelchair and verticalisation with the help of a standing frame are first steps. With the patient cardiovascular stable, gait restoration is put on the agenda. Instead of tone-inhibiting and gait preparatory maneuvers, patients should practice complex gait cycles repetitively. Treadmill training with partial body weight support enables the harness-secured patients to practice numerous steps assisted by two or three therapists. In controlled studies, it proved equally effective as walking on the floor. Gait machines, as the Lokomat or the Gait Trainer GTI, intend to relieve the strenuous effort for the therapists. For the GTI, several controlled trials showed a superior effect in acute stroke patients with respect to walking ability and velocity. For the ambulatory patient, aerobic treadmill training is effective to improve speed and endurance without worsening gait quality. Belt velocity and inclination are gradually increased so that the patients reach a predefined target heart rate. On the belt, patients walk more symmetrically, and higher velocities result in a facilitation of paretic muscles and render gait more efficient. In summary, gait rehabilitation has seen dramatic changes over the last years. More is to be expected. PMID:18356589

  10. Kinetic changes in gait during low magnitude military load carriage.

    PubMed

    Majumdar, Deepti; Pal, Madhu Sudan; Pramanik, Anilendu; Majumdar, Dhurjati

    2013-01-01

    Indian infantry soldiers carry smaller magnitudes of loads for operational requirements. The ground reaction forces (GRFs) and impulse responses of 10 healthy male Indian infantry soldiers were collected while they walked carrying operational loads between 4.2 and 17.5 kg (6.5-27.2% of mean body weight (BW)) and a control condition of no external load (NL). The GRF and impulse components were normalised for BW, and data for each load condition were compared with NL in each side applying one-way analysis of variance followed by Dunnett's post hoc test. Right foot data were compared with corresponding left foot GRF data for all load conditions and NL. There were significant increases in vertical and anteroposterior GRFs with increase in load. Left and right feet GRF data in corresponding load conditions were significantly different in anteroposterior plane. No significant change was observed in the temporal components of support phase of gait. Changes in impulse parameter were observed in the anteroposterior and vertical planes while carrying load greater than 23 and 16.6% of BW for the right foot and left foot, respectively. Result indicates that smaller magnitudes of loads produced kinetic changes proportional to system weight, similar to heavier loads with the possibility of increased injury risk. Observed smaller asymmetric changes in gait may be considered as postural adjustment due to load. Unique physical characteristics of Indian soldiers and the probable design shortcomings of the existing backpack might have caused significant changes in GRF and peak impulse during smaller load carriage. PMID:24164415

  11. Gait Characteristics in Nondisabled Community-Residing Nonagenarians

    PubMed Central

    Krishnamurthy, Mahesh; Verghese, Joe

    2006-01-01

    Objective To determine gait performance in community-residing nonagenarians. Design Nested case-control study. Setting Community. Participants Thirty-one nondisabled nonagenarians (17 women) and 170 young-old controls (age range, 70-85y) participating in a longitudinal study. Interventions Not applicable. Main Outcome Measures Systematic clinical and quantitative gait assessments. We also examined the association of gait velocity with death over a 1-year period. Results Nonagenarian men had better performance on all quantitative gait parameters examined compared with women. Male sex (?=.58; 95% confidence interval [CI], 9.95-38.89) and depressive symptoms (?=-.34; 95% CI, -6.73 to -0.04) were independently associated with gait velocity in multivariate linear regression models. The 6 hypertensive nonagenarians on angiotensin-converting enzyme (ACE) inhibitors had faster gait velocity (median, 103.1cm/s) compared with the 8 hypertensive nonagenarians not on ACE inhibitors (median, 77.5cm/s; P=.029). Nonagenarians had worse quantitative gait parameters compared with the young-old controls, though the differences were less marked when subjects with clinically normal gaits in both groups were compared. Gait velocity did not predict survival over 1-year follow-up. Conclusions Gait characteristics in nondisabled community-residing nonagenarians are associated with male sex, depressive symptoms, and medications. The quantitative gait measures in this sample of nondisabled nonagenarians provide a yardstick to compare younger age groups. PMID:16571395

  12. Fluctuation and synchronization of gait intervals and gait force profiles distinguish stages of Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Bartsch, Ronny; Plotnik, Meir; Kantelhardt, Jan W.; Havlin, Shlomo; Giladi, Nir; Hausdorff, Jeffrey M.

    2007-09-01

    We study the effects of Parkinson's disease (PD) on the long-term fluctuation and phase synchronization properties of gait timing (series of interstride intervals) as well as gait force profiles (series characterizing the morphological changes between the steps). We find that the fluctuations in the gait timing are significantly larger for PD patients and early PD patients, who were not treated yet with medication, compared to age-matched healthy controls. Simultaneously, the long-term correlations and the phase synchronization of right and left leg are significantly reduced in both types of PD patients. Surprisingly, long-term correlations of the gait force profiles are relatively weak for treated PD patients and healthy controls, while they are significantly larger for early PD patients. The results support the idea that timing and morphology of recordings obtained from a complex system can contain complementary information.

  13. [Three-Dimensional Ultrasonic Gait Analysis in Schizophrenic Patients

    PubMed

    Putzhammer, Albert; Heindl, Bernhard; Müller, Jürgen; Broll, Karin; Pfeiff, Liane; Perfahl, Maria; Hess, Linda; Koch, Horst

    2003-05-01

    Schizophrenic disorders as well as neuroleptic treatment can affect locomotion. The study assessed the influence of neuroleptic treatment on human gait via ultrasonic topometric gait analysis. In a control sample the test system proved high test-retest-reliability. Spatial and temporal gait parameters were assessed in schizophrenic patients without neuroleptic treatment (n = 12) and under treatment with conventional neuroleptics (n = 14) and re-assessed after treatment change to the atypical neuroleptic olanzapine in a repeated measures design. After switch from conventional neuroleptics to olanzapine patients showed an increase of gait velocity (p gait is affected by conventional neuroleptic treatment. The degree of impairment can be objectively measured by testing spatio-temporal and kinematic gait parameters via three-dimensional ultrasonic gait analysis. PMID:13130352

  14. Effects of gait velocity and center of mass acceleration during turning gait in old-old elderly women

    PubMed Central

    Shin, Sun-Shil; Yoo, Won-Gyu

    2015-01-01

    [Purpose] This study investigated gait velocity and center of mass acceleration in three directions during square and semicircular turning gait tasks in old-old elderly women. [Subjects] Fifteen community-dwelling, old-old elderly women (?75?years old) who could walk independently were recruited. [Methods] We measured gait velocity and center of mass acceleration in three directions using an accelerometer during two different turning gait tasks. [Results] The velocity during square turning was significantly slower than that during semicircular turning gait. There were no significant differences between gait tasks with respect to normalized antero-posterior, medo-lateral, or vertical center of mass acceleration. [Conclusion] Changing the direction of travel while walking regardless of turning angle is one of the greatest challenges for balance in old-old elderly people. Furthermore, gait velocity is a useful clinical marker for predicting falls in old-old elderly populations. PMID:26180319

  15. Development and testing of the Gait Assessment and Intervention Tool (G.A.I.T.): a measure of coordinated gait components.

    PubMed

    Daly, J J; Nethery, J; McCabe, J P; Brenner, I; Rogers, J; Gansen, J; Butler, K; Burdsall, R; Roenigk, K; Holcomb, J

    2009-04-15

    Recent neuroscience methods have provided the basis upon which to develop effective gait training methods for recovery of the coordinated components of gait after neural injury. We determined that there was not an existing observational measure that was, at once, adequately comprehensive, scored in an objectively-based manner, and capable of assessing incremental improvements in the coordinated components of gait. Therefore, the purpose of this work was to use content valid procedures in order to develop a relatively inexpensive, more comprehensive measure, scored with an objectively-based system, capable of incrementally scoring improvements in given items, and that was both reliable and capable of discriminating treatment response for those who had a stroke. Eight neurorehabilitation specialists developed criteria for the gait measure, item content, and scoring method. In subjects following stroke (>12 months), the new measure was tested for intra- and inter-rater reliability using the Intraclass Correlation Coefficient; capability to detect treatment response using Wilcoxon Signed Ranks Test; and discrimination between treatment groups, using the Plum Ordinal Regression. The Gait Assessment and Intervention Tool (G.A.I.T.) is a 31-item measure of the coordinated movement components of gait and associated gait deficits. It exhibited the following advantages: comprehensive, objective-based scoring method, incremental measurement of improvement within given items. The G.A.I.T. had good intra- and inter-rater reliability (ICC=.98, p=.0001, 95% CI=.95, .99; ICC=.83, p=.007, 95% CI=.32, .96, respectively. The inexperienced clinician who had training, had an inter-rater reliability with an experienced rater of ICC=.99 (p=.0001, CI=.97, .999). The G.A.I.T. detected improvement in response to gait training for two types of interventions: comprehensive gait training (z=-2.93, p=.003); and comprehensive gait training plus functional electrical stimulation (FES; z=-3.3, p=.001). The G.A.I.T. was capable of discriminating between two gait training interventions, showing an additive advantage of FES to otherwise comparable comprehensive gait training (parameter estimate=1.72, p=.021; CI, .25, 3.1). PMID:19146879

  16. Changes in gait when anticipating slippery floors

    Microsoft Academic Search

    Mark S. Redfern

    Falls precipitated by slipping are listed among the leading causes of injuries. The biomechanical analysis of such events is a necessary component of the slips\\/falls prevention research. One of the challenges of biomechanical studies is reproducing the unexpected nature of real-life slipping accidents. Thus, the goal of this study was to quantify changes in gait biomechanics when subjects anticipate slippery

  17. Changes in gait when anticipating slippery floors

    Microsoft Academic Search

    Rakié Cham; Mark S Redfern

    2002-01-01

    Falls precipitated by slipping are listed among the leading causes of injuries. The biomechanical analysis of such events is a necessary component of the slips\\/falls prevention research. One of the challenges of biomechanical studies is reproducing the unexpected nature of real-life slipping accidents. Thus, the goal of this study was to quantify changes in gait biomechanics when subjects anticipate slippery

  18. Kinematic Gait Analysis in Equine Carpal Lameness

    Microsoft Academic Search

    W. Back; A. Barneveld; P. R. Van Weeren; A. J. Van den Bogert

    1993-01-01

    Gait analysis plays a major role in the clinical evaluation of equine lameness. It is generally accepted that the clinician expresses the grade of lameness as a subjective score. In this study lameness was objectively assessed using a standardized transient lameness model, in which lameness was induced by intra-articular injection of bacterial endotoxin into the radiocarpal joint of ponies. Lameness

  19. Ratite Footprints and the Stance and Gait

    E-print Network

    Olsen, Paul E.

    footprints of the Mesozoic Era attributed to theropod dinosaurs. Of par- ticular interest,'(i) the rheaRatite Footprints and the Stance and Gait of Mesozoic Theropods KEVIN PADIAN AND PAUL E. OLSEN, and the toes and claws leave no drag marks. These are all characteristic of Mesozoic theropod (and ornithopod

  20. Gait pattern estimation for intelligent bionic leg

    Microsoft Academic Search

    Fei Wang; Shiguang Wen; Chengdong Wu

    2008-01-01

    Intelligent bionic leg (IBL) can restitute walking function for above-knee amputees. To realize symmetrical stable walking, IBL must be able to perceive the movement intention of amputee so as to actuate its knee joint accordingly when walking on various terrains with different cadences and stride length. Gait pattern estimation schemes using thigh kinematic data based on two classical pattern recognition

  1. Hemiparetic gait following stroke. Part I: Characteristics

    Microsoft Academic Search

    Sandra J. Olney; Carol Richards

    1996-01-01

    The biomechanical patterns that characterize the gait of persons who have sustained a stroke are reviewed. Reduced walking speed and longer stance phases, greater on the unaffected side, are reported. Variations in joint excursions include several deviations at initial contact and reduced excursions during swing. Electromyographic patterns have provided a classification method. Joint moment reports were variable, but included high

  2. Neurological update: emerging issues in gait disorders.

    PubMed

    Lewis, Simon J G

    2015-06-01

    Gait disorders represent a common and diverse challenge in Neurological practice. The literature on this field is expanding and is seeking to address mainstream clinical issues as well as a greater understanding of pathophysiological mechanisms. This update will introduce a range of these concepts. PMID:25736555

  3. A practical gait analysis system using gyroscopes

    Microsoft Academic Search

    Kaiyu Tong; Malcolm H Granat

    1999-01-01

    This study investigated the possibility of using uni-axial gyroscopes to develop a simple portable gait analysis system. Gyroscopes were attached on the skin surface of the shank and thigh segments and the angular velocity for each segment was recorded in each segment. Segment inclinations and knee angle were derived from segment angular velocities. The angular signals from a motion analysis

  4. Phase in ModelFree Perception of Gait Jeffrey E. Boyd

    E-print Network

    Boyd, Jeffrey E.

    ­of­motion phase analysis and a subjective description of gait, such as a normal gait versus a tired gait. For example, Murray et al. [12] show a detailed analysis of the gaits for several normal humans. The analysisPhase in Model­Free Perception of Gait Jeffrey E. Boyd Dept. of Computer Science University

  5. Motor bearing fluting

    Microsoft Academic Search

    J. A. Lawson

    1993-01-01

    Electrical motor bearing fluting has been defined as damage due to electrical current discharge through a motor bearing. Bearing race metal is electroplated onto the bearing balls. Close inspection reveals microscopic pits on bearing ball and race surfaces. A DC motor frame was completely isolated from ground except by a single grounding conductor with applied armature and field voltage. No

  6. Intersegmental coordination of gait after hemorrhagic stroke.

    PubMed

    Chow, John W; Stokic, Dobrivoje S

    2015-01-01

    We compared gait using the planar law of intersegmental coordination between 14 hemorrhagic stroke subjects walking at a self-selected normal speed (56 ± 21 cm/s) and 15 age-matched healthy controls walking at a very slow speed (56 ± 19 cm/s). Sagittal plane elevation angles of the thigh, shank, and foot segments were submitted to principal component analysis. Additional outcome measures included the range of elevation angle and timing of peak elevation angle of the thigh, shank, and foot segments. The range of elevation angles at the shank and foot was significantly smaller in the paretic leg than non-paretic and control legs. Also, the peak elevation angle at the thigh occurred significantly later in the gait cycle in the paretic than control leg. Gait of both stroke and control subjects followed the planar law with the first two principal components explaining approximately 99% of the variance. However, the three-dimensional trajectory of elevation angles (gait loop) in stroke subjects deviated from the typical teardrop shape bilaterally, which was more exaggerated in the paretic leg. Compared to the non-paretic and control legs, the paretic leg showed significantly increased absolute loading of the thigh elevation angle and decreased absolute loadings of the shank and foot elevation angles on the first principal component, whereas the opposite was observed for the second principal component. Despite following the planar law, the gait of chronic stroke subjects is characterized by atypical timing of the thigh motion and disrupted intersegmental coordination of both legs. PMID:25224705

  7. Alpine Skiing With total knee ArthroPlasty (ASWAP): effects on gait asymmetries.

    PubMed

    Pötzelsberger, B; Lindinger, S J; Stöggl, T; Buchecker, M; Müller, E

    2015-08-01

    The aim of the study was to examine the effect of a 12-week recreational skiing intervention on functional gait performance in people with unilateral total knee arthroplasty (TKA). Twenty-three older adults (71?±?5 years) were assigned to the intervention (IG) or control group (CG). Test time and ground reaction forces (GRF) were recorded at pre- and post-intervention and in the retention phase during functional gait tests. Ground contact was recorded bilaterally and divided into the weight acceptance and push-off phases. In IG, a faster stair descent time (16%) was observed at post-test with no further change at the retention test. The asymmetry indices for all analyzed variables were decreased in stair descent and during weight acceptance in stair ascent and level walking without further changes between post- and retention test. The reduced asymmetries occurred mainly because of increased loading of the operated leg. Most variables were unchanged in CG. Similar to the force data, the asymmetry index for temporal stride characteristics was reduced in all stair descent variables. These results demonstrate that alpine skiing as a leisure-time activity has a beneficial effect on gait performance and leads to a more balanced load distribution between the legs during daily activities. PMID:26083702

  8. Epidemiology of Gait Disorders in Community-Residing Older Adults

    PubMed Central

    Verghese, Joe; LeValley, Aaron; Hall, Charles B.; Katz, Mindy J.; Ambrose, Anne F.; Lipton, Richard B.

    2006-01-01

    OBJECTIVES: To study the epidemiology of gait disorders in community-residing older adults and their association with death and institutionalization. DESIGN: Community-based cohort study. SETTING: Bronx County and the research center at Albert Einstein College of Medicine. PARTICIPANTS: The Einstein Aging study recruited 488 adults aged 70 to 99 between 1999 and 2001. At entry and during annual visits over 5 years, subjects received clinical evaluations to determine presence of neurological or nonneurological gait abnormalities. MEASUREMENTS: Prevalence and incidence of gait disorders based on clinical evaluations and time to institutionalization and death. RESULTS: Of 468 subjects (95.9%) with baseline gait evaluations, 168 had abnormal gaits: 70 neurological, 81 nonneurological, and 17 both. Prevalence of abnormal gait was 35.0% (95% confidence interval (CI)=28.6-42.1). Incidence of abnormal gait was 168.6 per 1,000 person-years (95% CI=117.4-242.0) and increased with age. Men had a higher incidence of neurological gait abnormalities, whereas women had a higher incidence of nonneurological gaits. Abnormal gaits were associated with greater risk of institutionalization and death (hazard ratio (HR)=2.2, 95% CI=1.5-3.2). The risk was strongly related to severity of impairment; subjects with moderate to severe gait abnormalities (HR=3.2, 95% CI=1.9-5.2) were at higher risk than those with mild gait abnormalities (HR=1.8, 95% CI=1.0-2.8). CONCLUSION: The incidence and prevalence of gait disorders are high in community-residing older adults and are associated with greater risk of institutionalization and death. PMID:16460376

  9. Mediolateral balance and gait stability in older adults.

    PubMed

    Eduardo Cofré Lizama, L; Pijnappels, Mirjam; Rispens, Sietse M; Reeves, N Peter; Verschueren, Sabine M; van Dieën, Jaap H

    2015-06-01

    Early detection of balance impairment is crucial to identify individuals who may benefit from interventions aimed to prevent falls, which is a major problem in aging societies. Since mediolateral balance deteriorates with aging, we proposed a mediolateral balance assessment (MELBA) tool that uses a CoM-tracking task of predictable sinusoidal and unpredictable multisine targets. This method has shown to be reliable and sensitive to aging effect, however, it is not known whether it can predict performance on common daily-life tasks such as walking. This study aimed to determine whether MELBA is an ecologically valid tool by correlating its outputs with a measure of mediolateral gait stability known to be predictive of falls. Nineteen community-dwelling older adults (72±5 years) tracked predictable and unpredictable target displacements at increasing frequencies with their CoM by shifting their weight sideward. Response delay (phase-shift) and amplitude difference (gain) between the CoM and target in the frequency domain were used to quantify performance. To assess gait stability, the local divergence exponent was calculated using mediolateral accelerations with an inertial sensor when walking on a treadmill (LDETR) and in daily-life (LDEDL) for one week. Pearson product-moment correlation analyses were performed to determine correlations between performance on MELBA tasks and LDE. Results show that phase-shift bandwidth for the predictable target (range above -90°) was significantly correlated with LDETR whereas phase-shift bandwidth for the unpredictable target was significantly correlated with LDEDL. In conclusion MELBA is an ecologically valid tool for mediolateral balance assessment in community-dwelling older adults who exhibit subtle balance impairments. PMID:25953503

  10. Gait pattern of heifers before and after claw trimming: a high-speed cinematographic study on a treadmill.

    PubMed

    Meyer, S W; Weishaupt, M A; Nuss, K A

    2007-02-01

    The manner in which the claws contacted the ground at the walk was evaluated in 18 healthy heifers. The animals were filmed before and after claw trimming while walking on a treadmill using high-speed cinematography (500 frames/s). For each limb, 4 consecutive steps were recorded from a side and a frontal plane. The objectives of the study were to evaluate 1) the order of claw contact with the treadmill surface, 2) the initial claw contact area, and 3) the effect of trimming on claw contact patterns. The heifers placed their front feet on the ground in a plane sagittal to the shoulders, whereas the hind feet were advanced more toward the median plane. Before trimming, the lateral claws contacted the ground before the medial in 83% of front and 100% of hind limbs. Trimming changed the percentage to 92% in the front and to 97% in the hind limbs. The percentage with which the heel of the lateral claws became the region of initial contact with the ground increased from 47 to 64% in the front feet and from 50 to 78% in the hind feet. In the medial claws of the forelimbs, claw trimming shifted the region of initial contact from the toe to the abaxial wall and heel. In the hind limbs, the main region of initial contact of the medial claws became the abaxial wall. Weight bearing by the medial claw became visibly apparent only during the midstance, propulsion, and push-off phases. "Heel first" contact of the lateral claws in the front and hind limbs may be the normal gait pattern in cattle. On hard surfaces, this pattern may lead to overload and predispose to disease, especially in the hind limbs. PMID:17235142

  11. [Clinical gait analysis--methods, limitations and possible applications].

    PubMed

    Kopf, A; Pawelka, S; Kranzl, A

    1998-01-01

    Human gait is a complex and cyclic movement. Gait analysis of human walking can be done either without any technical support, or in combination with complex and expensive equipment. Modern gait analysis is based on the integration of multiple components to derive a complete analysis of gait. These methods may include observation, videotaping, electromyography, kinematics, kinetics and energetics. The results gained from these methods may then be used to determine the treatment course of a subject with gait abnormalities or to document the effects of therapeutical intervention. The purpose of this article is to provide an overview of the most common used methods in gait analysis. Emphasis will be placed on the type of information that can be derived from each component and how this information can be used clinically. PMID:9576022

  12. Effects of orthosis on balance and gait in healthy adults

    PubMed Central

    Kim, Myung-Joon; Choi, Yeong-Deok; Lee, Jung-Ho

    2015-01-01

    [Purpose] This study evaluated the effects of an oral orthosis that can change body alignment on the balance ability and gait of healthy adults. [Subjects and Methods] The subjects of this study were 21 University students. A gait analyzer was used to analyze the subjects’ balance ability and gait quality. Two walking speeds were used: 2?km/h, a comfortable speed, and 4?km/h, a slightly faster walking speed. [Results] The step length, and base of gait at 2?km/h differed significantly after the intervention. The total step time and step length increased significantly after the intervention. Furthermore, the total base of gait decreased significantly after the intervention. The step times of the left lower limb at 4?km/h differed significantly after the intervention. [Conclusion] The oral orthosis tested positively affects the balance ability and gait of healthy adults.

  13. The Golden Ratio of Gait Harmony: Repetitive Proportions of Repetitive Gait Phases

    PubMed Central

    Iosa, Marco; Marchetti, Fabio; Morone, Giovanni; Caltagirone, Carlo; Paolucci, Stefano; Peppe, Antonella

    2013-01-01

    In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number ? known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with ?, the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620?±?0.058, that between stance and the swing phase was 1.629?±?0.173, and that between swing and the double support phase was 1.684?±?0.357. All these ratios did not differ significantly from each other (F = 0.870, P = 0.422, repeated measure analysis of variance) or from ? (P = 0.670, 0.820, 0.422, resp., t-tests). The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait. PMID:23862161

  14. Robot Assisted Gait Training With Active Leg Exoskeleton (ALEX)

    Microsoft Academic Search

    Sai K. Banala; Seok Hun Kim; Sunil K. Agrawal; John P. Scholz

    2009-01-01

    Gait training of stroke survivors is crucial to facilitate neuromuscular plasticity needed for improvements in functional walking ability. Robot assisted gait training (RAGT) was developed for stroke survivors using active leg exoskeleton (ALEX) and a force-field controller, which uses assist-as-needed paradigm for rehabilitation. In this paradigm undesirable gait motion is resisted and assistance is provided towards desired motion. The force-field

  15. Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training

    PubMed Central

    2010-01-01

    Background Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on individuals with incomplete spinal cord injury (iSCI). Methods Eleven patients with iSCI participated in a single training session with the gait rehabilitation robot Lokomat. The patients were exposed to four different training modes in random order: During both non-cooperative position control and compliant impedance control, fixed timing of movements was provided. During two variants of the patient-cooperative path control approach, free timing of movements was enabled and the robot provided only spatial guidance. The two variants of the path control approach differed in the amount of additional support, which was either individually adjusted or exaggerated. Joint angles and torques of the robot as well as muscle activity and heart rate of the patients were recorded. Kinematic variability, interaction torques, heart rate and muscle activity were compared between the different conditions. Results Patients showed more spatial and temporal kinematic variability, reduced interaction torques, a higher increase of heart rate and more muscle activity in the patient-cooperative path control mode with individually adjusted support than in the non-cooperative position control mode. In the compliant impedance control mode, spatial kinematic variability was increased and interaction torques were reduced, but temporal kinematic variability, heart rate and muscle activity were not significantly higher than in the position control mode. Conclusions Patient-cooperative robot-aided gait training with free timing of movements made individuals with iSCI participate more actively and with larger kinematic variability than non-cooperative, position-controlled robot-aided gait training. PMID:20828422

  16. Gait attentional load at different walking speeds.

    PubMed

    Nascimbeni, Alberto; Minchillo, Marco; Salatino, Adriana; Morabito, Ursula; Ricci, Raffaella

    2015-01-01

    Gait is an attention-demanding task even in healthy young adults. However, scant evidence exists about the attentional load required at various walking speeds. The aim of this study was to investigate motor-cognitive interference while walking at spontaneous, slow and very slow speed on a treadmill while carrying out a backward counting task, in a group (n = 22) of healthy young participants. Cognitive performance was also assessed while sitting. Higher DT cost on the cognitive task was found at spontaneous and very slow walking speed, while at slow walking speed the cognitive task was prioritized with higher DT cost on the motor task. The attentional allocation during DT depends on walking speed with gait prioritization at spontaneous and very slow speed that likely represent more challenging motor conditions. PMID:25270327

  17. Totally frictionless magnetic bearing

    NASA Astrophysics Data System (ADS)

    Dodakian, Wayne; Bulman, John

    2000-11-01

    A totally frictionless magnetic bearing has been developed which supports a rotor in a contactless manner. The rotor is held in a magnetic potential well via repulsive forces only. Vertical and lateral restoring forces are provided to the rotor passively via permanent magnets in such an arrangement so as to support the weight of the rotor and provide it with a high degree of lateral stability. Axial stability of the rotor is provided by the use of an electromagnet which is controlled by a PID control loop. Information on the axial position of the rotor is provided to the circuit by use of an infrared LED and IR phototransistor. To prevent unwanted oscillations of the rotor’s axial position from occurring, an oscillation sensor in the form of an inductive pick-up coil of high impedance provides signals to the oscillation sensing portion of the circuit, which in turn feeds the oscillation dampening circuit. The use of only repulsive forces in stabilizing the rotor means that there will be no eddy current losses or hysterisis losses. Such a frictionless magnetic bearing can, for example be used in rotational oscillation experiments and ultra low loss watt-hour meters, which are of great importance to utility companies. When properly tuned, the total power requirements of the circuit is a mere 40mW, which is less than the 80 mW used by present day watt-hour meters.

  18. Cognitive Contributions to Gait and Falls: Evidence and Implications

    PubMed Central

    Amboni, Marianna; Barone, Paolo; Hausdorff, Jeffrey M.

    2014-01-01

    Dementia and gait impairments often coexist in older adults and patients with neurodegenerative disease. Both conditions represent independent risk factors for falls. The relationship between cognitive function and gait has recently received increasing attention. Gait is no longer considered merely automated motor activity but rather an activity that requires executive function and attention as well as judgment of external and internal cues. In this review, we intend to: (1) summarize and synthesize the experimental, neuropsychological, and neuroimaging evidence that supports the role played by cognition in the control of gait; and (2) briefly discuss the implications deriving from the interplay between cognition and gait. In recent years, the dual task paradigm has been widely used as an experimental method to explore the interplay between gait and cognition. Several neuropsychological investigations have also demonstrated that walking relies on the use of several cognitive domains, including executive-attentional function, visuospatial abilities, and even memory resources. A number of morphological and functional neuroimaging studies have offered additional evidence supporting the relationship between gait and cognitive resources. Based on the findings from 3 lines of studies, it appears that a growing body of evidence indicates a pivotal role of cognition in gait control and fall prevention. The interplay between higher-order neural function and gait has a number of clinical implications, ranging from integrated assessment tools to possible innovative lines of interventions, including cognitive therapy for falls prevention on one hand and walking program for reducing dementia risk on the other. PMID:24132840

  19. Detection of abnormalities in a human gait using smart shoes

    NASA Astrophysics Data System (ADS)

    Kong, Kyoungchul; Bae, Joonbum; Tomizuka, Masayoshi

    2008-03-01

    Health monitoring systems require a means for detecting and quantifying abnormalities from measured signals. In this paper, a new method for detecting abnormalities in a human gait is proposed for an improved gait monitoring system for patients with walking problems. In the previous work, we introduced a fuzzy logic algorithm for detecting phases in a human gait based on four foot pressure sensors for each of the right and left foot. The fuzzy logic algorithm detects the gait phases smoothly and continuously, and retains all information obtained from sensors. In this paper, a higher level algorithm for detecting abnormalities in the gait phases obtained from the fuzzy logic is discussed. In the proposed algorithm, two major abnormalities are detected 1) when the sensors measure improper foot pressure patterns, and 2) when the human does not follow a natural sequence of gait phases. For mathematical realization of the algorithm, the gait phases are dealt with by a vector analysis method. The proposed detection algorithm is verified by experiments on abnormal gaits as well as normal gaits. The experiment makes use of the Smart Shoes that embeds four bladders filled with air, the pressure changes in which are detected by pressure transducers.

  20. Enhanced data consistency of a portable gait measurement system

    NASA Astrophysics Data System (ADS)

    Lin, Hsien-I.; Chiang, Y. P.

    2013-11-01

    A gait measurement system is a useful tool for rehabilitation applications. Such a system is used to conduct gait experiments in large workplaces such as laboratories where gait measurement equipment can be permanently installed. However, a gait measurement system should be portable if it is to be used in clinics or community centers for aged people. In a portable gait measurement system, the workspace is limited and landmarks on a subject may not be visible to the cameras during experiments. Thus, we propose a virtual-marker function to obtain positions of unseen landmarks for maintaining data consistency. This work develops a portable clinical gait measurement system consisting of lightweight motion capture devices, force plates, and a walkway assembled from plywood boards. We evaluated the portable clinic gait system with 11 normal subjects in three consecutive days in a limited experimental space. Results of gait analysis based on the verification of within-day and between-day coefficients of multiple correlations show that the proposed portable gait system is reliable.

  1. Dynamic Principles of Gait and Their Clinical Implications

    PubMed Central

    Donelan, J. Maxwell

    2010-01-01

    A healthy gait pattern depends on an array of biomechanical features, orchestrated by the central nervous system for economy and stability. Injuries and other pathologies can alter these features and result in substantial gait deficits, often with detrimental consequences for energy expenditure and balance. An understanding of the role of biomechanics in the generation of healthy gait, therefore, can provide insight into these deficits. This article examines the basic principles of gait from the standpoint of dynamic walking, an approach that combines an inverted pendulum model of the stance leg with a pendulum model of the swing leg and its impact with the ground. The heel-strike at the end of each step has dynamic effects that can contribute to a periodic gait and its passive stability. Biomechanics, therefore, can account for much of the gait pattern, with additional motor inputs that are important for improving economy and stability. The dynamic walking approach can predict the consequences of disruptions to normal biomechanics, and the associated observations can help explain some aspects of impaired gait. This article reviews the basic principles of dynamic walking and the associated experimental evidence for healthy gait and then considers how the principles may be applied to clinical gait pathologies. PMID:20023002

  2. Gait Correlation Analysis Based Human Identification

    PubMed Central

    2014-01-01

    Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x), vertical axis (y), and temporal axis (t). By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features' dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance. PMID:24592144

  3. AURALISATION OF ROLLING BEARINGS

    Microsoft Academic Search

    Michael Vorländer; João Henrique; Diniz Guimarães

    Monitoring the operating conditions of rolling bearings and prediction of the remaining lifetime of bearings is one of the most crucial tasks in machine diagnosis. This work presents the results of the auralization of structure-borne sound in bearings and the transmission in machines. These signals correspond to the vibration measured on the machine's housing generated by cylindrical and ball bearings

  4. Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  5. Alterations in gait speed and age do not fully explain the changes in gait mechanics associated with healthy older women.

    PubMed

    Alcock, L; Vanicek, N; O'Brien, T D

    2013-04-01

    Older adults exhibit modified gait patterns compared to the young, adopting movement strategies in response to changes in musculoskeletal function. Investigating the functional mobility of older women is particularly important because of their increased life expectancy and greater falls risk compared to men. We explored the relationships between gait parameters and age in healthy older women whilst accounting for declining gait speeds. Kinematic and kinetic data were collected from thirty-nine women (60-83 years) whilst walking at a comfortable cadence. Regression analysis assessed the capacity of gait speed and age to explain the variance in gait associated with older age. Speed explained the majority of variance in many gait parameters. By including age in the regression, the total explained variance (R2) for foot clearance (70%), ankle plantarflexion angle (30%), peak ankle plantarflexor moment (58%), and hip power generation (56%) were significantly (p<0.05) greater than for speed alone. Nonetheless, changes in speed and age did not fully explain the variance in gait mechanics associated with older age and other contributing factors must exist. Losses of 1.2%/year in gait speed were predicted by age, exceeding previous predictions of -0.7%/year. Furthermore, the accumulation of apparently small decreases of 0.2 cm/year in peak foot-to-ground clearance has clinical implications and offers insight into the mechanisms by which gait becomes hazardous in older age. PMID:23122897

  6. Introduction to ball bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    The purpose of a ball bearing is to provide a relative positioning and rotational freedom while transmitting a load between two structures, usually a shaft and a housing. For high rotational speeds (e.g., in gyroscope ball bearings) the purpose can be expanded to include rotational freedom with practically no wear in the bearing. This condition can be achieved by separating the bearing parts with a coherent film of fluid known as an elastohydrodynamic film. This film can be maintained not only when the bearing carries the load on a shaft, but also when the bearing is preloaded to position the shaft to within micro- or nano-inch accuracy and stability. Background information on ball bearings is provided, different types of ball bearings and their geometry and kinematics are defined, bearing materials, manufacturing processes, and separators are discussed. It is assumed, for the purposes of analysis, that the bearing carries no load.

  7. High efficiency magnetic bearings

    NASA Technical Reports Server (NTRS)

    Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

    1993-01-01

    Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

  8. Musculoskeletal stiffness changes linearly in response to increasing load during walking gait.

    PubMed

    Caron, Robert R; Lewis, Cara L; Saltzman, Elliot; Wagenaar, Robert C; Holt, Kenneth G

    2015-04-13

    Development of biologically inspired exoskeletons to assist soldiers in carrying load is a rapidly expanding field. Understanding how the body modulates stiffness in response to changing loads may inform the development of these exoskeletons and is the purpose of the present study. Seventeen subjects walked on a treadmill at a constant preferred walking velocity while nine different backpack loading conditions ranging from 12.5% to 40% bodyweight (BW) were introduced in an ascending and then descending order. Kinematic data were collected using Optotrak, a 3D motion analysis system, and used to estimate the position of the center of mass (COM). Two different estimates of stiffness were computed for the stance phase of gait. Both measures of stiffness were positively and linearly related to load magnitudes, with the slopes of the relationships being larger for the descending than the ascending conditions. These results indicate that changes in mechanical stiffness brought about in the musculoskeletal system vary systematically during increases in load to ensure that critical kinematic variables measured in a previous publication remain invariant (Caron et al., 2013). Changes in stiffness and other kinematics measured at the 40% BW condition suggest a boundary in which gait stiffness control limit is reached and a new gait pattern is required. Since soldiers are now carrying up to 96% of body weight, the need for research with even heavier loads is warranted. These findings have implications on the development of exoskeletons to assist in carrying loads. PMID:25678200

  9. A novel shear reduction insole effect on the thermal response to walking stress, balance, and gait.

    PubMed

    Wrobel, James S; Ammanath, Peethambaran; Le, Tima; Luring, Christopher; Wensman, Jeffrey; Grewal, Gurtej S; Najafi, Bijan; Pop-Busui, Rodica

    2014-11-01

    Shear stresses have been implicated in the formation of diabetes-related foot ulcers. The aim of this study was to evaluate the effect of a novel shear-reducing insole on the thermal response to walking, balance, and gait. Twenty-seven diabetes peripheral neuropathy patients were enrolled and asked to take 200 steps in both intervention and standard insoles. Thermal foot images of the feet were taken at baseline (1) following a 5-minute temperature acclimatization and (2) after walking. Testing order was randomized, and a 5-minute washout period was used between testing each insole condition. Sudomotor function was also assessed. Gait and balance were measured under single and dual task conditions using a validated body worn sensor system. The mean age was 65.1 years, height was 67.3 inches, weight was 218 pounds, and body mass index was 33.9, 48% were female, and 82% had type 2 diabetes. After walking in both insole conditions, foot temperatures increased significantly in standard insoles. The intervention insole significantly reduced forefoot and midfoot temperature increases (64.1%, P = .008; 48%, P = .046) compared to standard insoles. There were significant negative correlations with sudomotor function and baseline temperatures (r = .53-.57). The intervention demonstrated 10.4% less gait initiation double support time compared to standard insoles (P = .05). There were no differences in static balance measures. We found significantly lower forefoot and midfoot temperature increases following walking with shear-reducing insoles compared to standard insoles. We also found improvements in gait. These findings merit future study for the prevention of foot ulcer. PMID:25107709

  10. Clinical gait and stepping performance measures in older adults

    Microsoft Academic Search

    N. B. Alexander; A. Goldberg

    2006-01-01

    Problems with ambulation and mobility are frequent problems in older adults. Each year, about one in 100 older adults develops new severe mobility disability. Assessment of abnormal gait constitutes a major component of clinical practice and may lead to fall reduction. Clinicians can benefit from simple gait and mobility assessment tools to be used in busy clinical settings. This review

  11. The Role of Executive Function and Attention in Gait

    PubMed Central

    Yogev, Galit; Hausdorff, Jeffrey M.; Giladi, Nir

    2008-01-01

    Until recently, gait was generally viewed as a largely automated motor task, requiring minimal higher-level cognitive input. Increasing evidence, however, links alterations in executive function and attention to gait disturbances. This review discusses the role of executive function and of attention in healthy walking and gait disorders while summarizing the relevant, recent literature. We describe the variety of gait disorders that may be associated with different aspects of executive function, and discuss the changes occurring in executive function as a result of aging and disease as well the potential impact of these changes on gait. The attentional demands of gait are often tested using dual tasking methodologies. Relevant studies in healthy adults and patients are presented, as are the possible mechanisms responsible for the deterioration of gait during dual tasking. Lastly, we suggest how assessments of executive function and attention could be applied in the clinical setting as part of the process of identifying and understanding gait disorders and fall risk. PMID:18058946

  12. Adaptive impedance control of a robotic orthosis for gait rehabilitation.

    PubMed

    Hussain, Shahid; Xie, Sheng Q; Jamwal, Prashant K

    2013-06-01

    Intervention of robotic devices in the field of physical gait therapy can help in providing repetitive, systematic, and economically viable training sessions. Interactive or assist-as-needed (AAN) gait training encourages patient voluntary participation in the robotic gait training process which may aid in rapid motor function recovery. In this paper, a lightweight robotic gait training orthosis with two actuated and four passive degrees of freedom (DOFs) is proposed. The actuated DOFs were powered by pneumatic muscle actuators. An AAN gait training paradigm based on adaptive impedance control was developed to provide interactive robotic gait training. The proposed adaptive impedance control scheme adapts the robotic assistance according to the disability level and voluntary participation of human subjects. The robotic orthosis was operated in two gait training modes, namely, inactive mode and active mode, to evaluate the performance of the proposed control scheme. The adaptive impedance control scheme was evaluated on ten neurologically intact subjects. The experimental results demonstrate that an increase in voluntary participation of human subjects resulted in a decrease of the robotic assistance and vice versa. Further clinical evaluations with neurologically impaired subjects are required to establish the therapeutic efficacy of the adaptive-impedance-control-based AAN gait training strategy. PMID:23193241

  13. Silhouette Analysis-Based Gait Recognition for Human Identification

    Microsoft Academic Search

    Liang Wang; Tieniu Tan; Huazhong Ning; Weiming Hu

    2003-01-01

    Human identification at a distance has recently gained growing interest from computer vision researchers. Gait recognition aims essentially to address this problem by identifying people based on the way they walk. In this paper, a simple but efficient gait recognition algorithm using spatial-temporal silhouette analysis is proposed. For each image sequence, a background subtraction algorithm and a simple correspondence procedure

  14. Passivity Based Control Of The Compass Gait Biped

    Microsoft Academic Search

    Mark W. Spong

    1999-01-01

    . In this paper we discuss the passivity based control of the two-link robotknown as the Compass Gait Biped. Starting from a narrow region of initial conditions,the compass gait biped is capable of locomotion down shallow inclines without actuationor feedback control of any kind. We will discuss some feedback control strategiesthat can exploit these passive dynamics by shaping the energy

  15. Structure Preserving Optimal Control of Three-Dimensional Compass Gait

    E-print Network

    Leyendecker, Sigrid

    Structure Preserving Optimal Control of Three-Dimensional Compass Gait Sigrid Leyendecker, David con- siders the optimal control of a bipedal compass gait by modeling the double stance configuration compass biped model. This control task has been previously addressed with various biped models

  16. Waddling and Toddling: The Biomechanical Effects of an Immature Gait

    E-print Network

    Pontzer, Herman

    , as normal human gait and body proportions differ between adults and younger individuals. Human biped- alismWaddling and Toddling: The Biomechanical Effects of an Immature Gait Libby W. Cowgill,1 * Anna femur; ground reaction force; shape; walking ABSTRACT Femoral shape changes during the course of human

  17. Gait coordination after stroke: benefits of acoustically paced treadmill walking

    Microsoft Academic Search

    Melvyn Roerdink; Claudine JC Lamoth; Gert Kwakkel; P. C. van Wieringen; P. J. Beek

    2007-01-01

    BACKGROUND AND PURPOSE: Gait coordination often is compromised after stroke. The purpose of this study was to evaluate the efficacy of acoustically paced treadmill walking as a method for improving gait coordination in people after stroke. PARTICIPANTS: Ten people after stroke volunteered for the study and comprised the experimental group. Nine elderly people who were healthy served as a control

  18. Instrumenting gait with an accelerometer: A system and algorithm examination

    PubMed Central

    Godfrey, A.; Del Din, S.; Barry, G.; Mathers, J.C.; Rochester, L.

    2015-01-01

    Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required. PMID:25749552

  19. Methods, Applications and Limitations of Gait Analysis in Horses

    Microsoft Academic Search

    E. BARREY

    1999-01-01

    Over the last 30 years, the increase in interest in horses for racing and riding activities has stimulated scientific research in equine locomotion. This paper presents a review of the measurement methods and their applications used to assess equine locomotion. After describing gaits and velocity-related changes in stride variables, the current applications of gait analysis are presented. The economic consequences

  20. Individual Recognition by Kinematic-Based Gait Analysis

    Microsoft Academic Search

    Bir Bhanu; Ju Han

    2002-01-01

    Current gait recognition approaches only consider individuals walking frontopamllel to the image plane. This makes them inapplicoble for recognizing individuals walking from different angles with respect to the image plane. In this paper, we propose a kinematic-based approach to recognize individuals by gait. The proposed approach estimates 30 human walking parameters by performing a least squares fit of the 30

  1. Gait and electromyographic analysis of anterior cruciate ligament deficient subjects

    Microsoft Academic Search

    D. J. Beard; R. S. Soundarapandian; J. J. O'Connor; C. A. F. Dodd

    1996-01-01

    Some anterior cruciate ligament deficient (ACLD) patients can overcome passive sagittal joint laxity and maintain dynamic stability of the knee joint. Gait analysis with electromyographic (EMG) support was used in an attempt to identify mechanisms whereby ACLD individuals achieve this functional stability. A group of 18 patients with arthroscopically proven, unilateral, chronic (>6 months) ACLD had their gait assessed using

  2. Clinical gait analysis by neural networks: issues and experiences

    Microsoft Academic Search

    Monika Köhle; Dieter Merkl; Josef Kastner

    1997-01-01

    Clinical gait analysis is an area aiming at the provision of support for diagnoses and therapyconsiderations, the development of bio-feedback systems to train patients, and the recognition ofeffects of multiple diseases and still active compensation. The data recorded with ground reactionforce measurement platforms is a convenient starting point for gait analysis. We argue in favor ofusing the raw data from

  3. Gait biomechanics and the evolution of total joint replacement

    Microsoft Academic Search

    Thomas P. Andriacchi; Debra E. Hurwitz

    1997-01-01

    The history and evolution of total knee and total hip replacement has been influenced substantially by the knowledge obtained from gait analysis studies. Many of the mechanical problems associated with these devices have been analyzed and evaluated in terms of the mechanics of walking. The magnitude and pattern of the forces at the hip and knee joints derived from gait

  4. A continuous-wave (CW) radar for gait analysis

    Microsoft Academic Search

    Jonathan L. Geisheimer; William S. Marshall; Eugene Greneker

    2001-01-01

    A fully coherent, continuous-wave (CW) radar operating near 10.5 GHz has been developed to record the radar signature corresponding to the walking human gait. The received signal is the sum of Doppler shifted signals reflected from the various parts of the moving body. Since the legs, arms, and torso all move at different relative velocities throughout the gait cycle, the

  5. Factors Related to Gait Function in Post-stroke Patients

    PubMed Central

    Cho, Ki Hun; Lee, Joo Young; Lee, Kun Jae; Kang, Eun Kyoung

    2014-01-01

    [Purpose] Gait function after a stroke is an important factor for determining a patient’s ability to independently perform activities of daily living (ADL). The objective of this study was to elucidate the factors associated with gait function in post-stroke patients. [Subjects] Thirty-nine stroke patients (16 females and 23 males; average age 67.82 ± 10.96?years; post-onset duration: 200.18 ± 27.14 days) participated in this study. [Methods] Their gait function, motor function (Manual Muscle Test [MMT] and Brünnstrom stage), level of cognition (Mini-Mental State Examination score [MMSE], and the Loewenstein Occupational Therapy Cognitive Assessment for the Geriatric Population [LOTCA-G]), and ADL (Korean modified Barthel index [K-MBI]) were assessed. [Results] The degree of gait function showed significant positive correlations with the following variables: MMT of the elbow, knee, ankle and wrist; Brünnstrom stage; MMSE; LOTCA-G subscores except motor praxis; K-MBI. Stepwise linear regression analysis revealed the Brünnstrom stage was the only explanatory variable closely associated with gait level. [Conclusion] Gait function of post-stroke patients was related to motor function, cognition, and ADL. In particular, there is a significant association between gait level and the Brünnstrom stages, reflecting the importance of monitoring the motor recovery of gait function in post-stroke patients. PMID:25540503

  6. A portable, real-time, clinical gait velocity analysis system

    Microsoft Academic Search

    R. F. Weir; Dudley S. Childress

    1997-01-01

    A direct ultrasound ranging system (DURS) has been developed for the quantitative evaluation of gait velocity. DURS consists of a transponder worn by the subject, a base unit infrared (IR) emitter\\/ultrasound (US) receiver, and a laptop computer. During gait analysis the transponder is worn by the subject at the approximate level of the body center of mass. As the subject

  7. Control of the Compass Gait on Rough Terrain

    E-print Network

    Tedrake, Russ

    Essential model for dynamic walking on rough terrain: · Hip-actuated compass gait (CG) with leg inertia Essential model for dynamic walking on rough terrain: · Hip-actuated compass gait (CG) with leg inertia masses at hip (mh) and on each leg (m) ; · Passive pivot model for "toe" of stance leg · 5 States

  8. EVOLVING LEG CYCLES TO PRODUCE HEXAPOD GAITS GARY B. PARKER

    E-print Network

    Parker, Gary B.

    were not designed to take advantage of the full capa- bilities of the servo motor actuators. Each servo by dividing the prob- lem into two parts: leg cycle learning and gait cycle learning. Servo pulses required movement by the servos. The best means of combining these leg cycles into a gait cycle is learned

  9. Dynamic knee loads during gait predict proximal tibial bone distribution

    Microsoft Academic Search

    Debra E. Hurwitz; Dale R. Sumner; Thomas P. Andriacchi; David A. Sugar

    1998-01-01

    This study tested the validity of the prediction of dynamic knee loads based on gait measurements. The relationship between the predicted loads at the knee and the distribution of bone between the medial and lateral sides of the tibia was examined. The motion and external forces and moments at the knee were measured during gait and a statically determinate muscle

  10. Humanoid Soccer Gait Generation and Optimization Using Probability Distribution Models

    E-print Network

    Menegatti, Emanuele

    Humanoid Soccer Gait Generation and Optimization Using Probability Distribution Models Changjiu to generate and optimize various types of basic soccer-playing humanoid gaits for our humanoid soccer robot Robo-Erectus which has been one of pioneering humanoid soccer- playing robots in the Humanoid League

  11. Gait analysis in children and uncertainty assessment for Davis protocol and Gillette Gait Index.

    PubMed

    Assi, Ayman; Ghanem, Ismat; Lavaste, François; Skalli, Wafa

    2009-07-01

    The protocol of Davis is widely used in children's gait analysis, especially in cerebral palsy studies and its repeatability was evaluated primarily for adults. The aim of this research was to evaluate the uncertainty and repeatability of this protocol for children. 56 asymptomatic children aged 5-15 years performed the gait exam. Kinematics parameters and Gillette Gait Index (GGI) were calculated. 17 subjects performed the exam twice with markers replacement. Uncertainties on gait parameters were evaluated using repeatability study and Monte Carlo simulations. Uncertainty (2SD of test-retest differences) obtained on angles calculated by the protocol varied between +/-2 degrees and +/-3 degrees (for pelvis and hip in sagittal and frontal planes) and +/-14 degrees (for mean hip rotation). Uncertainty on GGI was +/-12 for healthy subjects. Monte Carlo simulations on 30 cerebral palsy children showed that the error on GGI could reach +/-100 and was correlated to GGI value (R2=0.92): 2SD=24+0.09xGGI. PMID:19321345

  12. DMRT3 is associated with gait type in Mangalarga Marchador horses, but does not control gait ability.

    PubMed

    Patterson, L; Staiger, E A; Brooks, S A

    2015-04-01

    The Mangalarga Marchador (MM) is a Brazilian horse breed known for a uniquely smooth gait. A recent publication described a mutation in the DMRT3 gene that the authors claim controls the ability to perform lateral patterned gaits (Andersson et al. 2012). We tested 81 MM samples for the DMRT3 mutation using extracted DNA from hair bulbs using a novel RFLP. Horses were phenotypically categorized by their gait type (batida or picada), as recorded by the Brazilian Mangalarga Marchador Breeders Association (ABCCMM). Statistical analysis using the plink toolset (Purcell, 2007) revealed significant association between gait type and the DMRT3 mutation (P = 2.3e-22). Deviation from Hardy-Weinberg equilibrium suggests that selective pressure for gait type is altering allele frequencies in this breed (P = 1.00e-5). These results indicate that this polymorphism may be useful for genotype-assisted selection for gait type within this breed. As both batida and picada MM horses can perform lateral gaits, the DMRT3 mutation is not the only locus responsible for the lateral gait pattern. PMID:25690906

  13. Overground robot assisted gait trainer for the treatment of drug-resistant freezing of gait in Parkinson disease.

    PubMed

    Pilleri, Manuela; Weis, Luca; Zabeo, Letizia; Koutsikos, Konstantinos; Biundo, Roberta; Facchini, Silvia; Rossi, Simonetta; Masiero, Stefano; Antonini, Angelo

    2015-08-15

    Freezing of Gait (FOG) is a frequent and disabling feature of Parkinson disease (PD). Gait rehabilitation assisted by electromechanical devices, such as training on treadmill associated with sensory cues or assisted by gait orthosis have been shown to improve FOG. Overground robot assisted gait training (RGT) has been recently tested in patients with PD with improvement of several gait parameters. We here evaluated the effectiveness of RGT on FOG severity and gait abnormalities in PD patients. Eighteen patients with FOG resistant to dopaminergic medications were treated with 15 sessions of RGT and underwent an extensive clinical evaluation before and after treatment. The main outcome measures were FOG questionnaire (FOGQ) global score and specific tasks for gait assessment, namely 10meter walking test (10MWT), Timed Up and Go test (TUG) and 360° narrow turns (360 NT). Balance was also evaluated through Fear of Falling Efficacy Scale (FFES), assessing self perceived stability and Berg Balance Scale (BBS), for objective examination. After treatment, FOGQ score was significantly reduced (P=0.023). We also found a significant reduction of time needed to complete TUG, 10MWT, and 360 NT (P=0.009, 0.004 and 0.04, respectively). By contrast the number of steps and the number of freezing episodes recorded at each gait task did not change. FFES and BBS scores also improved, with positive repercussions on performance on daily activity and quality of life. Our results indicate that RGT is a useful strategy for the treatment of drug refractory FOG. PMID:26048047

  14. Gait Variability Is Associated with Subclinical Brain Vascular Abnormalities in High-Functioning Older Adults

    Microsoft Academic Search

    Caterina Rosano; Jennifer Brach; Stephanie Studenski; W. T. Longstreth Jr.; Anne B. Newman

    2007-01-01

    Background: Gait variability is an index of how much gait parameters, such as step length, change from one step to the next. Gait variability increases with age and in individuals affected by cortical and subcortical neurodegenerative conditions, and it is associated with falls and incident mobility disability. The brain anatomical correlates of gait variability have not been studied in high-functioning

  15. Comparative analysis of the gait disorder of normal pressure hydrocephalus and Parkinson's disease

    Microsoft Academic Search

    H Stolze; J P Kuhtz-Buschbeck; H Drücke; K Jöhnk; M Illert; G Deuschl

    2001-01-01

    OBJECTIVESComparative gait analyses in neurological diseases interfering with locomotion are of particular interest, as many hypokinetic gait disorders have the same main features. The aim of the present study was (1) to compare the gait disturbance in normal pressure hydrocephalus and Parkinson's disease; (2) to evaluate which variables of the disturbed gait pattern respond to specific treatment in both diseases;

  16. Dual Gait Generative Models for Human Motion Estimation From a Single Camera

    Microsoft Academic Search

    Xin Zhang; Guoliang Fan

    2010-01-01

    This paper presents a general gait representation framework for video-based human motion estimation. Specifically, we want to estimate the kinematics of an unknown gait from image sequences taken by a single camera. This approach involves two generative models, called the kinematic gait generative model (KGGM) and the visual gait generative model (VGGM), which represent the kinematics and appearances of a

  17. Incremental Learning for Video-based Gait Recognition with LBP-Flow

    E-print Network

    Little, Jim

    as the starting point of gait analysis, since gait researchers [1], [2], [3] managed to identify the subjects1 Incremental Learning for Video-based Gait Recognition with LBP-Flow Maodi Hu, Yunhong Wang, Member, IEEE, Zhaoxiang Zhang, Member, IEEE, De Zhang, and James J. Little, Member, IEEE Abstract--Gait

  18. 2004 International Conference on Image Processing (ICIP) AN ANGULAR TRANSFORM OF GAIT SEQUENCESFOR

    E-print Network

    Plataniotis, Konstantinos N.

    ,Ontario MSS 3G4, Canada 1.nikos@conm.toronto.edu ABSTRACT A new system is proposccd for gait analysis-surveillance and reniote identification systems. Existing approaches for gait sequence analysis try to capture as much gait Labs at the Universityof Tamlo. automatic gait recognilion. Recently. an image analysis nicthod- ology

  19. Muscle contributions to vertical and fore-aft accelerations are altered in subjects with crouch gait

    E-print Network

    Delp, Scott

    of Bioengineering, Stanford University, Stanford, CA, USA c The James R. Gage Center for Gait and Motion Analysis Crouch gait Induced acceleration analysis Muscle Simulation A B S T R A C T The goals of this study were palsy and crouch gait. Analysis of these simulations revealed that during unimpaired gait the quadriceps

  20. Natural gait generation of biped robot based on captured human motion image

    Microsoft Academic Search

    Seungsuk Ha; Youngjoon Han; Hernsoo Hahn

    2008-01-01

    This paper proposes a new method of generating a natural and stable gait pattern for biped robots, imitating a human gait. For this purpose, human gait patterns are analyzed in terms of torque in the sagittal as well as ZMP in the frontal plane. These two gait parameters are used as the object function of the modified genetic algorithm which

  1. Gait Rehabilitation Therapy Using Robot Generated Force Fields Applied at the Pelvis

    E-print Network

    Mavroidis, Constantinos

    Gait Rehabilitation Therapy Using Robot Generated Force Fields Applied at the Pelvis ABSTRACT The Robotic Gait Rehabilitation (RGR) Trainer was designed and built to target secondary gait deviations tissue dynamics. KEYWORDS: Force field, robotic gait rehabilitation, pelvis. 1 INTRODUCTION Each year

  2. Introduction to magnetic bearings

    NASA Technical Reports Server (NTRS)

    Skowronski, Lori; Bisese, Anne

    1993-01-01

    Multi-axis suspension has several advantages over single axis system, in that it provides control of an object with precision in two or three orthogonal axes. In this report, we discuss the primary use of magnetic-bearing suspension and it's relevance to what was formally known as NASA's Annular Suspension and Pointing System (ASPS). This system is an experimental pointing system with applications for the space shuttle and the space station programs. The objectives behind this magnetic suspension research project are to provide insight to the use of the ASPS configuration, to control the solar panels of the space station. This is important to maintain the correct position of the panels in relation to the sun and orbiting space station for the continuous supply of solar energy. Since the panels are suspended, they can be aligned with minimum outside interference. The approach of using magnetic suspension technology guarantees mechanical isolation since there are no contacting surfaces. This isolation reduces vibration transmission and mechanical wear which in turn extends the life of the payload and of the carrier. It should be noted that ASPS has a high pointing accuracy along the line of 0.01 arc-second. This research will be done in a laboratory setting by incorporating five bearing stations and one motion control station. We will attempt to suspend an object of dead weight similar to that of a solar panel. The long term applications may include deep-space navigation, fire control in weapon systems, and an improved mass transit system.

  3. Tracking Polar Bears

    NSDL National Science Digital Library

    WGBH Educational Foundation

    2008-01-17

    In this interactive activity adapted from the USGS Alaska Science Center, track the movements of a polar bear as it migrates across the changing Arctic sea ice and compare the paths of four different polar bears.

  4. Axial Halbach Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2008-01-01

    Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

  5. Video-Based Human Motion Estimation by Part-Whole Gait Manifold Learning

    Microsoft Academic Search

    Guoliang Fan; Xin Zhang

    \\u000a This chapter presents a general gait representation framework for video-based human motion estimation that involves gait modeling\\u000a at both the whole and part levels. Our goal is to estimate the kinematics of an unknown gait from image sequences taken by\\u000a a single camera. This approach involves two generative models, called the kinematic gait generative model (KGGM) and the visual\\u000a gait

  6. A collisional perspective on quadrupedal gait dynamics

    PubMed Central

    Lee, David V.; Bertram, John E. A.; Anttonen, Jennifer T.; Ros, Ivo G.; Harris, Sarah L.; Biewener, Andrew A.

    2011-01-01

    The analysis of terrestrial locomotion over the past half century has focused largely on strategies of mechanical energy recovery used during walking and running. In contrast, we describe the underlying mechanics of legged locomotion as a collision-like interaction that redirects the centre of mass (CoM). We introduce the collision angle, determined by the angle between the CoM force and velocity vectors, and show by computing the collision fraction, a ratio of actual to potential collision, that the quadrupedal walk and gallop employ collision-reduction strategies while the trot permits greater collisions. We provide the first experimental evidence that a collision-based approach can differentiate quadrupedal gaits and quantify interspecific differences. Furthermore, we show that this approach explains the physical basis of a commonly used locomotion metric, the mechanical cost of transport. Collision angle and collision fraction provide a unifying analysis of legged locomotion which can be applied broadly across animal size, leg number and gait. PMID:21471189

  7. Gait Deviations in Children with Autism Spectrum Disorders: A Review

    PubMed Central

    Kindregan, Deirdre; Gallagher, Louise; Gormley, John

    2015-01-01

    In recent years, it has become clear that children with autism spectrum disorders (ASDs) have difficulty with gross motor function and coordination, factors which influence gait. Knowledge of gait abnormalities may be useful for assessment and treatment planning. This paper reviews the literature assessing gait deviations in children with ASD. Five online databases were searched using keywords “gait” and “autism,” and 11 studies were found which examined gait in childhood ASD. Children with ASD tend to augment their walking stability with a reduced stride length, increased step width and therefore wider base of support, and increased time in the stance phase. Children with ASD have reduced range of motion at the ankle and knee during gait, with increased hip flexion. Decreased peak hip flexor and ankle plantar flexor moments in children with ASD may imply weakness around these joints, which is further exhibited by a reduction in ground reaction forces at toe-off in children with ASD. Children with ASD have altered gait patterns to healthy controls, widened base of support, and reduced range of motion. Several studies refer to cerebellar and basal ganglia involvement as the patterns described suggest alterations in those areas of the brain. Further research should compare children with ASD to other clinical groups to improve assessment and treatment planning. PMID:25922766

  8. Gait deviations in children with autism spectrum disorders: a review.

    PubMed

    Kindregan, Deirdre; Gallagher, Louise; Gormley, John

    2015-01-01

    In recent years, it has become clear that children with autism spectrum disorders (ASDs) have difficulty with gross motor function and coordination, factors which influence gait. Knowledge of gait abnormalities may be useful for assessment and treatment planning. This paper reviews the literature assessing gait deviations in children with ASD. Five online databases were searched using keywords "gait" and "autism," and 11 studies were found which examined gait in childhood ASD. Children with ASD tend to augment their walking stability with a reduced stride length, increased step width and therefore wider base of support, and increased time in the stance phase. Children with ASD have reduced range of motion at the ankle and knee during gait, with increased hip flexion. Decreased peak hip flexor and ankle plantar flexor moments in children with ASD may imply weakness around these joints, which is further exhibited by a reduction in ground reaction forces at toe-off in children with ASD. Children with ASD have altered gait patterns to healthy controls, widened base of support, and reduced range of motion. Several studies refer to cerebellar and basal ganglia involvement as the patterns described suggest alterations in those areas of the brain. Further research should compare children with ASD to other clinical groups to improve assessment and treatment planning. PMID:25922766

  9. Understanding gait control in post-stroke: implications for management.

    PubMed

    Verma, Rajesh; Arya, Kamal Narayan; Sharma, Pawan; Garg, R K

    2012-01-01

    The role of the brain in post-stroke gait is not understood properly, although the ability to walk becomes impaired in more than 80% of post-stroke patients. Most, however, regain some ability to walk with either limited mobility or inefficient, asymmetrical or unsafe gait. Conventional intervention focuses on support of weak muscles or body part by use of foot orthosis and walking aids. This review provides an overview of available evidence of neuro-kinesiology & neurophysiology of normal and post-stroke gait. The role of the spinal cord has been explored, more in animals than humans. Mammalian locomotion is based on a rhythmic, "pacemaker" activity of the spinal stepping generators. Bipedal human locomotion is different from quadripedal animal locomotion. However, knowledge derived from the spinal cord investigation of animals, is being applied for management of human gait dysfunction. The potential role of the brain is now recognized in the independent activation of muscles during walking. The brain modifies the gait pattern during the complex demands of daily activities. Though the exact role of the motor cortex in control of gait is unclear, available evidence may be applied to gait rehabilitation of post-stroke patients. PMID:22196422

  10. Observational gait assessment tools in paediatrics--a systematic review.

    PubMed

    Rathinam, Chandrasekar; Bateman, Andrew; Peirson, Janet; Skinner, Jane

    2014-06-01

    Instrumented gait analysis (IGA) is an expensive technique used to objectively detect gait abnormalities in children. Observational gait assessment is considered as a cost effective alternate for IGA in regular clinical practice. This article is aimed at systematically reviewing the available paediatric gait analysis tools and examines their reliability and validity compared to IGA. This review also examines the structure of these tools, their clinical use and limitations. Articles were searched from PubMed, CINHL, AMED, BNI, EMBASE, PEDro and Cochrane library from the earliest record on the database to December 2012. Hand searches were carried out in a few journals. Studies that examined children's gait using a structured assessment tool were included and analysed for their quality, reliability and validity. Pre-established criteria were used to judge the quality of methodology and reliability and validity. Five observational gait tools for children with Cerebral Palsy (CP) and one for children with Downs Syndrome were identified. Nine studies related to children with CP were enrolled for this review. None of the tools have accomplished the level of IGA's consistency. Edinburgh Visual Gait Score (EVGS) was found to have better reliability and validity than the other tools. Very limited studies were available for most of the gait assessment tools therefore their clinical use cannot be judged based on the existing evidence. EVGS was found to have better concurrent validity and reliability and it should be considered to assess CP gait in regular practice. Future work to investigate the use of low cost technology to improve observers' accuracy of EVGS is suggested. PMID:24798609

  11. Cryogenic Hybrid Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  12. Influence of gait analysis on decision-making for lower extremity orthopaedic surgery: Baseline data from a randomized controlled trial

    E-print Network

    Valero-Cuevas, Francisco

    gait analysis data are considered [3­8]. In addition, in patients who underwent gait analysis, 37 to evaluate patients with complex walking problems such as children with cerebral palsy (CP). Gait analysis-level surgical plan. Although gait analysis allows for a more accurate assessment of gait deviations than visual

  13. The Effect of Tai Chi Exercise on Gait Initiation and Gait Performance in Persons with Parkinson’s Disease

    PubMed Central

    Amano, Shinichi; Nocera, Joe R.; Vallabhajosula, Srikant; Juncos, Jorge L.; Gregor, Robert J.; Waddell, Dwight E.; Wolf, Steven L.; Hass, Chris J.

    2013-01-01

    Gait dysfunction and postural instability are two debilitating symptoms in persons with Parkinson’s disease (PD). Tai Chi exercise has recently gained attention as an attractive intervention for persons with PD because of its known potential to reduce falls and improve postural control, walking abilities, and safety at a low cost. The purpose of this report is to investigate the effect of Tai Chi exercise on dynamic postural control during gait initiation and gait performance in persons with idiopathic PD, and to determine whether these benefits could be replicated in two different environments, as complementary projects. In these two separate projects, a total of 45 participants with PD were randomly assigned to either a Tai Chi group or a control group. The Tai Chi groups in both projects completed a 16-week Tai Chi exercise session, while the control groups consisted of either a placebo (i.e., Qi-Gong) or non-exercise group. Tai Chi did not significantly improve Unified Parkinson’s Disease Rating Scale Part III score, selected gait initiation parameters or gait performance in either project. Combined results from both projects suggest that 16 weeks of class-based Tai Chi were ineffective in improving either gait initiation, gait performance, or reducing parkinsonian disability in this subset of persons with PD. Thus the use of short-term Tai Chi exercise should require further study before being considered a valuable therapeutic intervention for these domains in PD. PMID:23835431

  14. A robust real-time gait event detection using wireless gyroscope and its application on normal and altered gaits.

    PubMed

    Gouwanda, Darwin; Gopalai, Alpha Agape

    2015-02-01

    Gait events detection allows clinicians and biomechanics researchers to determine timing of gait events, to estimate duration of stance phase and swing phase and to segment gait data. It also aids biomedical engineers to improve the design of orthoses and FES (functional electrical stimulation) systems. In recent years, researchers have resorted to using gyroscopes to determine heel-strike (HS) and toe-off (TO) events in gait cycles. However, these methods are subjected to significant delays when implemented in real-time gait monitoring devices, orthoses, and FES systems. Therefore, the work presented in this paper proposes a method that addresses these delays, to ensure real-time gait event detection. The proposed algorithm combines the use of heuristics and zero-crossing method to identify HS and TO. Experiments involving: (1) normal walking; (2) walking with knee brace; and (3) walking with ankle brace for overground walking and treadmill walking were designed to verify and validate the identified HS and TO. The performance of the proposed method was compared against the established gait detection algorithms. It was observed that the proposed method produced detection rate that was comparable to earlier reported methods and recorded reduced time delays, at an average of 100 ms. PMID:25619613

  15. Gait asymmetry in patients with Parkinson's disease and elderly fallers: when does the bilateral coordination of gait require attention?

    PubMed

    Yogev, Galit; Plotnik, Meir; Peretz, Chava; Giladi, Nir; Hausdorff, Jeffrey M

    2007-03-01

    While it is known that certain pathologies may impact on left-right symmetry of gait, little is known about the mechanisms that contribute to gait symmetry or how high in the hierarchy of the control of gait symmetry is regulated in humans. To assess the contribution of cognitive function to gait symmetry, we measured gait asymmetry (GA) in three subject groups, patients with Parkinson's disease (PD, n = 21), idiopathic elderly fallers (n = 15), and healthy elderly controls (n = 11). All subjects walked, under two walking conditions: usual walking and dual tasking (cognitive loading) condition. For each subject, the swing time (SW) was calculated and averaged across strides for the left and right feet (SWL and SWR). GA was defined as: 100 x /ln(SWR/SWL)/. For both the PD patients and the elderly fallers GA values were significantly higher during the usual walking condition, as compared with the control group (P < 0.01). In addition, for both the PD patients and the elderly fallers, GA significantly increased when they walked and performed a dual task, compared with the usual walking condition (P < 0.003). In contrast, dual tasking did not affect the GA of the healthy controls (P = 0.518). GA was associated with gait speed and gait variability, but no correlations were found between GA and the asymmetry of the classic PD motor symptoms. Thus, the results suggest that the ability to generate a steady, rhythmic walk with a bilaterally coordinated gait does not rely heavily on mental attention and cognitive resources in healthy older adults. In contrast, however, when gait becomes impaired and less automatic, GA apparently relies on cognitive input and attention. PMID:16972073

  16. An electric motor with magnetic bearings: A concept

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1973-01-01

    Because same magnetic flux is used to control rotor as to drive it, size, weight, and power required are minimized. Constant total current keeps motor torque invarient, and absence of mechanical bearings eliminates wear and reduces frictional power loss.

  17. Weight set

    NSDL National Science Digital Library

    N/A N/A (None; )

    2005-12-11

    Your skin covers and protects your body. Your skin can also detect pressure and weight. You can tell that a one gram weight feels lighter than a one kilogram weight because the receptors on your skin detect more pressure from a one kilogram weight compared to a one gram weight.

  18. Numerical limit analysis solutions for the bearing capacity factor N ?

    Microsoft Academic Search

    M. Hjiaj; A. V. Lyamin; S. W. Sloan

    2005-01-01

    Numerical limit analyses are applied to evaluate the self-weight bearing capacity factor for a rigid surface footing with a smooth or rough interface. To isolate the effect of the self-weight on the bearing capacity, the soil is modeled as a cohesionless frictional Mohr–Coulomb material. Assuming an associated flow rule, the true collapse load is bracketed to within 3.42% by computing

  19. Visualising gait symmetry/asymmetry from acceleration data.

    PubMed

    Yoneyama, Mitsuru

    2015-07-01

    Accelerometry-based quantification of gait symmetry/asymmetry is a promising approach for objectively evaluating gait dysfunctions. An important step in the application of this method in clinical settings is to develop reliable gait asymmetry measures and tools for visualising them to create easy-to-understand presentations for both clinicians and patients. This paper describes a new self-adaptive algorithm for estimating motion trajectory from acceleration data and visualising the degree of its asymmetry in 3D space. Two new parameters are introduced to capture asymmetric walking patterns based on the assessment of 3D autocorrelation and biphasicity of the motion trajectory. The performance of our algorithm is confirmed by analysing gait data collected from 245 healthy subjects. The proposed method may be clinically useful in tracking the process of recovering from pathology or injury after rehabilitation. PMID:24266651

  20. Effect of gait on formation of thermal environment inside footwear.

    PubMed

    Shimazaki, Yasuhiro; Murata, Masaaki

    2015-07-01

    In this study, the relationship between the gait condition and foot temperature distributions inside footwear was investigated using subject experiments. Mechanical, physical, and physiological variables such as the foot contact force, landing speed, and metabolic heat generation were also measured. Gait motion measurements showed that a large contact force was concentrated in the small area of the heel at the initial contact and later at the forefoot. A faster gait produced a larger contact force, higher landing velocity, higher skin temperature, and larger metabolism during gait. The temperature at the bottom of the foot increased, and the temperature on the upper side decreased. The metabolic heat generation had a basic impact on the temperature profile, and skin temperatures tended to increase gradually. In addition, high-temperature-elevation regions such as the big toe and heel coincided with regions with high-contact loads, which suggested a relationship between the temperature elevation and contact load. PMID:25766423

  1. Virtual sensory feedback for gait improvement in neurological patients.

    PubMed

    Baram, Yoram

    2013-01-01

    We review a treatment modality for movement disorders by sensory feedback. The natural closed-loop sensory-motor feedback system is imitated by a wearable virtual reality apparatus, employing body-mounted inertial sensors and responding dynamically to the patient's own motion. Clinical trials have shown a significant gait improvement in patients with Parkinson's disease using the apparatus. In contrast to open-loop devices, which impose constant-velocity visual cues in a "treadmill" fashion, or rhythmic auditory cues in a "metronome" fashion, requiring constant vigilance and attention strategies, and, in some cases, instigating freezing in Parkinson's patients, the closed-loop device improved gait parameters and eliminated freezing in most patients, without side effects. Patients with multiple sclerosis, previous stroke, senile gait, and cerebral palsy using the device also improved their balance and gait substantially. Training with the device has produced a residual improvement, suggesting virtual sensory feedback for the treatment of neurological movement disorders. PMID:24133478

  2. Interpolation function for approximating knee joint behavior in human gait

    NASA Astrophysics Data System (ADS)

    Toth-Ta?c?u, Mirela; Pater, Flavius; Stoia, Dan Ioan

    2013-10-01

    Starting from the importance of analyzing the kinematic data of the lower limb in gait movement, especially the angular variation of the knee joint, the paper propose an approximation function that can be used for processing the correlation among a multitude of knee cycles. The approximation of the raw knee data was done by Lagrange polynomial interpolation on a signal acquired using Zebris Gait Analysis System. The signal used in approximation belongs to a typical subject extracted from a lot of ten investigated subjects, but the function domain of definition belongs to the entire group. The study of the knee joint kinematics plays an important role in understanding the kinematics of the gait, this articulation having the largest range of motion in whole joints, in gait. The study does not propose to find an approximation function for the adduction-abduction movement of the knee, this being considered a residual movement comparing to the flexion-extension.

  3. Freezing of gait: a practical approach to management.

    PubMed

    Nonnekes, Jorik; Snijders, Anke H; Nutt, John G; Deuschl, Günter; Giladi, Nir; Bloem, Bastiaan R

    2015-07-01

    Freezing of gait is a common and disabling symptom in patients with parkinsonism, characterised by sudden and brief episodes of inability to produce effective forward stepping. These episodes typically occur during gait initiation or turning. Treatment is important because freezing of gait is a major risk factor for falls in parkinsonism, and a source of disability to patients. Various treatment approaches exist, including pharmacological and surgical options, as well as physiotherapy and occupational therapy, but evidence is inconclusive for many approaches, and clear treatment protocols are not available. To address this gap, we review medical and non-medical treatment strategies for freezing of gait and present a practical algorithm for the management of this disorder, based on a combination of evidence, when available, and clinical experience of the authors. Further research is needed to formally establish the merits of our proposed treatment protocol. PMID:26018593

  4. Low Power Shoe Integrated Intelligent Wireless Gait Measurement System

    NASA Astrophysics Data System (ADS)

    Wahab, Y.; Mazalan, M.; Bakar, N. A.; Anuar, A. F.; Zainol, M. Z.; Hamzah, F.

    2014-04-01

    Gait analysis measurement is a method to assess and identify gait events and the measurements of dynamic, motion and pressure parameters involving the lowest part of the body. This significant analysis is widely used in sports, rehabilitation as well as other health diagnostic towards improving the quality of life. This paper presents a new system empowered by Inertia Measurement Unit (IMU), ultrasonic sensors, piezoceramic sensors array, XBee wireless modules and Arduino processing unit. This research focuses on the design and development of a low power ultra-portable shoe integrated wireless intelligent gait measurement using MEMS and recent microelectronic devices for foot clearance, orientation, error correction, gait events and pressure measurement system. It is developed to be cheap, low power, wireless, real time and suitable for real life in-door and out-door environment.

  5. On using gait in forensic biometrics.

    PubMed

    Bouchrika, Imed; Goffredo, Michaela; Carter, John; Nixon, Mark

    2011-07-01

    Given the continuing advances in gait biometrics, it appears prudent to investigate the translation of these techniques for forensic use. We address the question as to the confidence that might be given between any two such measurements. We use the locations of ankle, knee, and hip to derive a measure of the match between walking subjects in image sequences. The Instantaneous Posture Match algorithm, using Harr templates, kinematics, and anthropomorphic knowledge is used to determine their location. This is demonstrated using real CCTV recorded at Gatwick International Airport, laboratory images from the multiview CASIA-B data set, and an example of real scene of crime video. To access the measurement confidence, we study the mean intra- and inter-match scores as a function of database size. These measures converge to constant and separate values, indicating that the match measure derived from individual comparisons is considerably smaller than the average match measure from a population. PMID:21554307

  6. A Novel HMM Distributed Classifier for the Detection of Gait Phases by Means of a Wearable Inertial Sensor Network

    PubMed Central

    Taborri, Juri; Rossi, Stefano; Palermo, Eduardo; Patanè, Fabrizio; Cappa, Paolo

    2014-01-01

    In this work, we decided to apply a hierarchical weighted decision, proposed and used in other research fields, for the recognition of gait phases. The developed and validated novel distributed classifier is based on hierarchical weighted decision from outputs of scalar Hidden Markov Models (HMM) applied to angular velocities of foot, shank, and thigh. The angular velocities of ten healthy subjects were acquired via three uni-axial gyroscopes embedded in inertial measurement units (IMUs) during one walking task, repeated three times, on a treadmill. After validating the novel distributed classifier and scalar and vectorial classifiers-already proposed in the literature, with a cross-validation, classifiers were compared for sensitivity, specificity, and computational load for all combinations of the three targeted anatomical segments. Moreover, the performance of the novel distributed classifier in the estimation of gait variability in terms of mean time and coefficient of variation was evaluated. The highest values of specificity and sensitivity (>0.98) for the three classifiers examined here were obtained when the angular velocity of the foot was processed. Distributed and vectorial classifiers reached acceptable values (>0.95) when the angular velocity of shank and thigh were analyzed. Distributed and scalar classifiers showed values of computational load about 100 times lower than the one obtained with the vectorial classifier. In addition, distributed classifiers showed an excellent reliability for the evaluation of mean time and a good/excellent reliability for the coefficient of variation. In conclusion, due to the better performance and the small value of computational load, the here proposed novel distributed classifier can be implemented in the real-time application of gait phases recognition, such as to evaluate gait variability in patients or to control active orthoses for the recovery of mobility of lower limb joints. PMID:25184488

  7. Quantitative Gait Analysis Detects Significant Differences in Movement between Osteoarthritic and Nonosteoarthritic Guinea Pig Strains before and after Treatment with Flunixin Meglumine.

    PubMed

    Santangelo, K S; Kaeding, A C; Baker, S A; Bertone, A L

    2014-01-01

    A computer-aided gait analysis system was used to contrast two guinea pig strains with differing propensity for osteoarthritis (OA), with/without administration of a nonsteroidal anti-inflammatory drug. Walking speed and static/dynamic gait parameters were determined at baseline. Flunixin meglumine was given and animals were evaluated 4, 24, and 72 hours after treatment. Body weight was compared using unpaired t-tests. Knee joints were histologically evaluated using species-specific criteria; indices were analyzed using one-way ANOVA, Kruskal-Wallis test, followed by Dunn's multiple comparisons. A generalized linear model followed by Tukey's posttests juxtaposed gait parameters; walking speed was a covariate for other outcome measures. Body weight was not different between strains; OA-prone animals demonstrated more progressive chondropathy. At baseline, OA-prone animals had slower walking speeds, narrower hind limb bases of support, shorter stride lengths, and slower limb swing speeds relative to OA-resistant animals. These differences were not detected 4 or 24 hours after treatment. By 72 hours, OA-prone animals had returned to baseline values. These findings indicate a distinct voluntary gait pattern in a rodent model of bilateral primary OA, modification of which may allow rapid screening of novel therapies. Flunixin meglumine temporarily permitted OA-prone animals to move in a manner that was analogous to OA-resistant animals. PMID:24963402

  8. The effects of a suspended-load backpack on gait

    Microsoft Academic Search

    Xu Xu; Simon M. Hsiang; Gary A. Mirka

    2009-01-01

    A suspended-load backpack is a device that is designed to capture the mechanical energy created as a suspended backpack load oscillates vertically on the back during gait. The objective of the current study was to evaluate the effect of a suspended-load backpack system on selected temporal and kinetics parameters describing gait. Nine male participants carried a suspended-load backpack as they

  9. Gait Analysis of Knee Arthritis Treated With Hyaluronic Acid

    Microsoft Academic Search

    Don Kevin Lester; Kuan Zhang

    2010-01-01

    Self-reported studies have demonstrated efficacy of hyaluronic acid (HA) therapy. Gait analysis may objectively demonstrate changes associated with HA therapy. Fifty-three consecutive patients with unilateral osteoarthritis (OA) of the knee were evaluated with a validated and sensitive gait laboratory previously used for gonarthrosis. Two 100-meter walks were performed before and after HA therapy. Nineteen parameters were measured. In addition, the

  10. Further results on control of the compass gait biped

    Microsoft Academic Search

    Mark W. Spong; Gagandeep Bhatia

    2003-01-01

    This paper continues our investigations into the passivity-based control of the compass gait biped. It was shown in [Spong, M.W., 1999] for the compass gait biped, and in [Spong, M.W., and Bullo, F., 2002] for the general case, that a passive limit cycle for a given constant slope can be made slope invariant via potential energy shaping control. In this

  11. Data management in gait analysis for clinical applications

    Microsoft Academic Search

    MG Benedetti; F Catani; A Leardini; E Pignotti; S Giannini

    1998-01-01

    Objective. To study the reliability of gait analysis data obtained using the Calibrated Anatomical System Technique (cast) protocol and to verify the suitability and repeatability of the extraction of a number of parameters from the waveforms obtained.Design. The experimental protocol and the parametric analysis technique were applied on a population of able-bodied subjects.Background. The clinical interpretation process of gait data

  12. Wire Weight

    USGS Multimedia Gallery

    Wire weight is lowered to water surface to measure stage at a site. Levels are made to the wire weights elevation from known benchmarks to ensure correct readings. This wire weight is located along the Missouri River in Bismarck, ND....

  13. Automatic identification of gait events using an instrumented sock

    PubMed Central

    2011-01-01

    Background Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. Methods We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. Results Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. Conclusions This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance. PMID:21619570

  14. Temporal and spatial organization of gait-related electrocortical potentials.

    PubMed

    Knaepen, Kristel; Mierau, Andreas; Tellez, Helio Fernandez; Lefeber, Dirk; Meeusen, Romain

    2015-07-10

    To advance gait rehabilitation research it is of great importance to understand the supraspinal control of walking. In this study, the temporal and spatial characteristics of averaged electrocortical activity during treadmill walking in healthy subjects was assessed. Electroencephalography data were recorded from 32 scalp locations, averaged across trials, and related to phases of the gait cycle based on the detection of left heel strike. A characteristic temporal pattern of positive and negative potentials, similar to movement-related cortical potentials, and related to the gait cycle was observed over the cortical leg representation area. Source localization analysis revealed that mainly the primary somatosensory, somatosensory association, primary motor and cingulate cortex were activated during walking. The negative peaks of the gait-related cortical potential were associated with activity predominantly in the cingulate and prefrontal cortex, while the primary motor, primary somatosensory and somatosensory association cortex were mainly active during the positive peaks. This study identified gait-related cortical potentials during walking. The results indicate a widely distributed cortical network involved in gait control. PMID:26003448

  15. Self-calibrating view-invariant gait biometrics.

    PubMed

    Goffredo, Michela; Bouchrika, Imed; Carter, John N; Nixon, Mark S

    2010-08-01

    We present a new method for viewpoint independent gait biometrics. The system relies on a single camera, does not require camera calibration, and works with a wide range of camera views. This is achieved by a formulation where the gait is self-calibrating. These properties make the proposed method particularly suitable for identification by gait, where the advantages of completely unobtrusiveness, remoteness, and covertness of the biometric system preclude the availability of camera information and specific walking directions. The approach has been assessed for feature extraction and recognition capabilities on the SOTON gait database and then evaluated on a multiview database to establish recognition capability with respect to view invariance. Moreover, tests on the multiview CASIA-B database, composed of more than 2270 video sequences with 65 different subjects walking freely along different walking directions, have been performed. The obtained results show that human identification by gait can be achieved without any knowledge of internal or external camera parameters with a mean correct classification rate of 73.6% across all views using purely dynamic gait features. The performance of the proposed method is particularly encouraging for application in surveillance scenarios. PMID:19884085

  16. The Incredible Water Bear

    NSDL National Science Digital Library

    Martin Mach

    This image-rich Micscape Magazine article explores how water bears can be found almost everywhere yet are still unknown to almost everybody, why there are relatively few light microscope photographs of water bears in the literature and on the Web, and how light microscopy can outperform scanning electron microscopy when viewing these animals. It includes a list of historical references, early sketches, and colorful images of water bears, also known as tardigrades.

  17. Bear Spray Safety Program

    USGS Publications Warehouse

    Blome, C.D.; Kuzniar, R.L.

    2009-01-01

    A bear spray safety program for the U.S. Geological Survey (USGS) was officially initiated by the Firearms Safety Committee to address accident prevention and to promote personnel training in bear spray and its transportation, storage, and use for defense against wild animals. Used as part of a system including firearms, or used alone for those who choose not to carry a firearm, bear spray is recognized as an effective tool that can prevent injury in a wild animal attack.

  18. Differences in cortical activation between observing one's own gait and the gait of others: a functional near-infrared spectroscopy study.

    PubMed

    Fuchigami, Takeshi; Morioka, Shu

    2015-03-01

    Using functional near-infrared spectroscopy, we investigated cortical activation while participants observed their own gait and the gait of others. Further, we compared the vividness of motor imagery induced by observing one's own and the gait of others. Participants were instructed to perform a gait observation task. The task had two conditions: observing video clips of one's own walking and observing video clips of other individuals walking. After observing the videos, the participants were asked to evaluate the vividness of the mental image of the observed gait on a visual analog scale. When observing one's own gait, the right dorsal premotor cortex and the superior parietal lobule were activated, whereas when observing the gait of others, the left inferior parietal lobule was activated. Observing one's own gait induced imagery that was significantly more vivid than that induced when viewing the gait of others. We suggest that observing one's own gait generates a representation of one's own body in the brain and induces more vivid gait imagery. PMID:25674903

  19. Objective assessment of abnormal gait in patients with rheumatoid arthritis using a smartphone.

    PubMed

    Yamada, Minoru; Aoyama, Tomoki; Mori, Shuhei; Nishiguchi, Shu; Okamoto, Kazuya; Ito, Tatsuaki; Muto, Shinyo; Ishihara, Tatsuya; Yoshitomi, Hiroyuki; Ito, Hiromu

    2012-12-01

    A disturbance in gait pattern is a serious problem in patients with rheumatoid arthritis (RA). The aim of the present study was to examine the utility of the smartphone gait analysis application in patients with RA. The smartphone gait analysis application was used to assess 39 patients with RA (age 65.9 ± 10.0 years, disease duration 11.9 ± 9.4 years) and age-matched control individuals (mean age, 69.1 ± 5.8 years). For all RA patients, the following data were obtained: disease activity score (DAS) 28, modified health assessment questionnaire (mHAQ), and assessment of walking ability. Patients walked 20 m at their preferred speed, and trunk acceleration was measured using a Smartphone. After signal processing, we calculated the following gait parameters for each measurement terminal: peak frequency (PF), autocorrelation peak (AC), and coefficient of variance (CV) of the acceleration peak intervals. The gait parameters of RA and control groups were compared to examine the comparability of the 2 groups. Criterion-related validity was determined by evaluating the correlation between gait parameters and clinical parameters using Spearman's correlation coefficient. The RA group showed significantly lower scores for the walking speed, AC, and CV than the control group. There were no significant differences in PF. PF (gait cycle) was mildly associated with gait speed (P < 0.05). AC (gait balance) was moderately associated with the DAS, mHAQ, gait ability, and gait speed (P < 0.05). CV (gait variability) was moderately associated with the DAS, gait ability, and gait speed (P < 0.05). This is the first study to examine the use of a smartphone device for gait pattern measurement. The results suggest that some gait parameters recorded using the smartphone represent an acceptable assessment tool for gait in patients with RA. PMID:22193221

  20. Rotordynamics and bearing design of turbochargers

    NASA Astrophysics Data System (ADS)

    Chen, Wen Jeng

    2012-05-01

    Turbochargers have gained significant attention in recent years. They are already widely used in automotive, locomotive, and marine applications with diesel engines. They are also applied in the aerospace application to increase the engine performance now. The turbochargers used in automotive and aerospace industry are very light-weight with operating speeds above 100,000 rpm. The turbochargers used in locomotive and marine applications are relatively heavy in size and power compared to the automotive and aerospace applications, and the maximum continuous operating speeds are around 30,000 rpm depending on the diesel engine power rating. Floating ring bushings, semi-floating dampers, ball bearings, and ball bearings with dampers are commonly used in automotive applications for small turbochargers. However, these bearings may not be appropriate for large turbochargers in locomotive and marine applications. Instead, multi-lobed bearings with and without squeeze film dampers are commonly used in these heavy-duty turbochargers. This paper deals with the rotordynamic characteristics of larger turbochargers in locomotive and marine applications. Various bearing designs are discussed. Bearing design parameters are studied and optimal values are suggested. Test results are also presented to support the analytical simulation.

  1. Laboratory review: the role of gait analysis in seniors' mobility and fall prevention.

    PubMed

    Bridenbaugh, Stephanie A; Kressig, Reto W

    2011-01-01

    Walking is a complex motor task generally performed automatically by healthy adults. Yet, by the elderly, walking is often no longer performed automatically. Older adults require more attention for motor control while walking than younger adults. Falls, often with serious consequences, can be the result. Gait impairments are one of the biggest risk factors for falls. Several studies have identified changes in certain gait parameters as independent predictors of fall risk. Such gait changes are often too discrete to be detected by clinical observation alone. At the Basel Mobility Center, we employ the GAITRite electronic walkway system for spatial-temporal gait analysis. Although we have a large range of indications for gait analyses and several areas of clinical research, our focus is on the association between gait and cognition. Gait analysis with walking as a single-task condition alone is often insufficient to reveal underlying gait disorders present during normal, everyday activities. We use a dual-task paradigm, walking while simultaneously performing a second cognitive task, to assess the effects of divided attention on motor performance and gait control. Objective quantification of such clinically relevant gait changes is necessary to determine fall risk. Early detection of gait disorders and fall risk permits early intervention and, in the best-case scenario, fall prevention. We and others have shown that rhythmic movement training such as Jaques-Dalcroze eurhythmics, tai chi and social dancing can improve gait regularity and automaticity, thus increasing gait safety and reducing fall risk. PMID:20980732

  2. Gait in thoracolumbar/lumbar adolescent idiopathic scoliosis: effect of surgery on gait mechanisms

    PubMed Central

    Detrembleur, C.; Mousny, M.; Banse, X.

    2010-01-01

    For patients whose scoliosis progresses, surgery remains the ultimate way to correct and stabilise the deformity while maintaining as many mobile spinal segments as possible. In thoracolumbar/lumbar adolescent idiopathic scoliosis (AIS), the spinal fusion has to be extended to the lumbar spine. The use of anterior spinal fusion (ASF) instead of the classic posterior fusion (PSF) may preserve more distal spinal levels in attempt to limit the consequences of surgery on trunk mobility. The effects of surgery on body shape, pain and the decompensation phenomenon have all been well evaluated. Very few studies have addressed the effect of ASF or PSF on basic activities, such as walking. Before any treatment, AIS patients already have reduced pelvis, hip and shoulder motion when walking at a normal speed compared with adolescents without scoliosis (control group). Additionally, they have longer contraction time of the lumbar and pelvic muscles leading to an excessive energy cost and reduced muscle efficiency. In addition, if these changes are associated with spinal stiffness, spinal fusion could further negatively affect this pre-surgical inefficient walk. The goals of this study were (a) to compare pre- and 1-year post-surgery conditions in order to assess the effects of spinal arthrodesis on gait parameters and (b) to compare the anterior versus the posterior surgical approaches. Nineteen young females with thoracolumbar/lumbar AIS were assessed by radiological and clinical examination and by conventional gait analysis before surgery and at almost 12 months after surgery. Seven subjects underwent surgery using ASF and 12 using PSF. Three-dimensional gait analysis was performed on a motor-driven treadmill at spontaneous self-selected speed to record kinematic, electromyographic (EMG), mechanical and energetic measurements synchronously. Although it was expected that the instrumentation would modify the characteristics of normal walking, this study showed that surgery does not induce asymmetric gait or any significant differences between the ASP and the PSF surgery groups. One year after surgery, the changes observed consisted of improvements in the gait and mechanical parameters. In the PSF group, 11–14 vertebrae were fused while only 3–4 were fused in the ASF group. In both AIS groups, step length was increased by 4% and cadence reduced by 2%. There was a slight increase in pelvis and hip frontal motion. Only the transverse shoulder motion was mildly decreased by 1.5°. All the other gait parameters were left unchanged or were improved by surgery. Notably, the EMG timing activity did not change. The total muscular mechanical work (Wtot) increased by 6% mainly due to the external work (Wext), i.e. the work performed by the body muscles to move the body in its surroundings. The energy cost, although showing a tendency towards a reduction, remained globally excessive, probably due to the excessive co-contraction of the lumbo-pelvic muscles. PMID:20148341

  3. Gait in thoracolumbar/lumbar adolescent idiopathic scoliosis: effect of surgery on gait mechanisms.

    PubMed

    Mahaudens, Philippe; Detrembleur, C; Mousny, M; Banse, X

    2010-07-01

    For patients whose scoliosis progresses, surgery remains the ultimate way to correct and stabilise the deformity while maintaining as many mobile spinal segments as possible. In thoracolumbar/lumbar adolescent idiopathic scoliosis (AIS), the spinal fusion has to be extended to the lumbar spine. The use of anterior spinal fusion (ASF) instead of the classic posterior fusion (PSF) may preserve more distal spinal levels in attempt to limit the consequences of surgery on trunk mobility. The effects of surgery on body shape, pain and the decompensation phenomenon have all been well evaluated. Very few studies have addressed the effect of ASF or PSF on basic activities, such as walking. Before any treatment, AIS patients already have reduced pelvis, hip and shoulder motion when walking at a normal speed compared with adolescents without scoliosis (control group). Additionally, they have longer contraction time of the lumbar and pelvic muscles leading to an excessive energy cost and reduced muscle efficiency. In addition, if these changes are associated with spinal stiffness, spinal fusion could further negatively affect this pre-surgical inefficient walk. The goals of this study were (a) to compare pre- and 1-year post-surgery conditions in order to assess the effects of spinal arthrodesis on gait parameters and (b) to compare the anterior versus the posterior surgical approaches. Nineteen young females with thoracolumbar/lumbar AIS were assessed by radiological and clinical examination and by conventional gait analysis before surgery and at almost 12 months after surgery. Seven subjects underwent surgery using ASF and 12 using PSF. Three-dimensional gait analysis was performed on a motor-driven treadmill at spontaneous self-selected speed to record kinematic, electromyographic (EMG), mechanical and energetic measurements synchronously. Although it was expected that the instrumentation would modify the characteristics of normal walking, this study showed that surgery does not induce asymmetric gait or any significant differences between the ASP and the PSF surgery groups. One year after surgery, the changes observed consisted of improvements in the gait and mechanical parameters. In the PSF group, 11-14 vertebrae were fused while only 3-4 were fused in the ASF group. In both AIS groups, step length was increased by 4% and cadence reduced by 2%. There was a slight increase in pelvis and hip frontal motion. Only the transverse shoulder motion was mildly decreased by 1.5 degrees . All the other gait parameters were left unchanged or were improved by surgery. Notably, the EMG timing activity did not change. The total muscular mechanical work (W (tot)) increased by 6% mainly due to the external work (W (ext)), i.e. the work performed by the body muscles to move the body in its surroundings. The energy cost, although showing a tendency towards a reduction, remained globally excessive, probably due to the excessive co-contraction of the lumbo-pelvic muscles. PMID:20148341

  4. Bearing fatigue investigation 3

    NASA Technical Reports Server (NTRS)

    Nahm, A. H.; Bamberger, E. N.; Signer, H. R.

    1982-01-01

    The operating characteristics of large diameter rolling-element bearings in the ultra high speed regimes expected in advanced turbine engines for high performance aircraft were investigated. A high temperature lubricant, DuPont Krytox 143 AC, was evaluated at bearing speeds to 3 million DN. Compared to the results of earlier, similar tests using a MIL-L-23699 (Type II) lubricant, bearings lubricated with the high density Krytox fluid showed significantly higher power requirements. Additionally, short bearing lives were observed when this fluid was used with AISI M50 bearings in an air atmosphere. The primary mode of failure was corrosion initiated surface distress (fatigue) on the raceways. The potential of a case-carburized bearing to sustain a combination of high-tangential and hertzian stresses without experiencing race fracture was also investigated. Limited full scale bearing tests of a 120 mm bore ball bearing at a speed of 25,000 rpm (3 million DN) indicated that a carburized material could sustain spalling fatigue without subsequent propagation to fracture. Planned life tests of the carburized material had to be aborted, however, because of apparent processing-induced material defects.

  5. Grizzly bears and forestry

    Microsoft Academic Search

    S. E. Nielsen; R. H. M. Munro; E. L. Bainbridge; G. B. Stenhouse; M. S. Boyce

    2004-01-01

    We assessed the occurrence and fruit production of 13 grizzly bear foods in west-central Alberta, Canada, to better understand use of clearcuts by grizzly bears. Comparisons were made between clearcuts and upland forest stands, while specific models describing food or fruit occurrence within clearcuts were developed from canopy, clearcut age, scarification, and terrain-related variables using logistic regression. Ants, Equisetum spp.,

  6. Superconducting bearings in flywheels

    Microsoft Academic Search

    T. A. Coombs; A. M. Campbell; I. Ganney; W. Lo; T. Twardowski; B. Dawson

    1998-01-01

    Investigations are being carried out into the use of superconducting magnetic bearings to levitate Energy storage flywheels. In a planned program of work, Cambridge University are aiming to produce a practical bearing system for Pirouette™. The Pirouette™ system is designed to provide 5 kWh of recoverable energy which is currently recoverable at a rate of 5 kW (future revisions will

  7. Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2007-01-01

    Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

  8. Prediction of gait recovery in spinal cord injured individuals trained with robotic gait orthosis

    PubMed Central

    2014-01-01

    Background Motor impairment is a major consequence of spinal cord injury (SCI). Earlier studies have shown that robotic gait orthosis (e.g., Lokomat) can improve an SCI individual’s walking capacity. However, little is known about the differential responses among different individuals with SCI. The present longitudinal study sought to characterize the distinct recovery patterns of gait impairment for SCI subjects receiving Lokomat training, and to identify significant predictors for these patterns. Methods Forty SCI subjects with spastic hypertonia at their ankles were randomly allocated to either control or intervention groups. Subjects in the intervention group participated in twelve 1-hour Lokomat trainings over one month, while control subjects received no interventions. Walking capacity was evaluated in terms of walking speed, functional mobility, and endurance four times, i.e. baseline, 1, 2, and 4 weeks after training, using the 10-Meter-Walking, Timed-Up-and-Go, and 6-Minute-Walking tests. Growth Mixture Modeling, an analytical framework for stratifying subjects based on longitudinal changes, was used to classify subjects, based on their gait impairment recovery patterns, and to identify the effects of Lokomat training on these improvements. Results Two recovery classes (low and high walking capacity) were identified for each clinical evaluation from both the control and intervention groups. Subjects with initial high walking capacity (i.e. shorter Timed-Up-and-Go time, higher 10-Meter-Walking speed and longer 6-Minute-Walking distance) displayed significant improvements in speed and functional mobility (0.033 m/s/week and–0.41 s/week respectively); however no significant change in endurance was observed. Subjects with low walking capacity exhibited no significant improvement. The membership in these two classes—and thus prediction of the subject’s gait improvement trajectory over time—could be determined by the subject’s maximum voluntary torque at the ankle under both plantar-and dorsi-flexion contractions determined prior to any training. Conclusion Our findings demonstrate that subjects responded to Lokomat training non-uniformly, and should potentially be grouped based on their likely recovery patterns using objective criteria. Further, we found that the subject’s ankle torque can predict whether he/she would benefit most from Lokomat training prior to the therapy. These findings are clinically significant as they can help individualize therapeutic programs that maximize patient recovery while minimizing unnecessary efforts and costs. PMID:24661681

  9. Improvements in Sleep Quality and Gait Speed After Cataract Surgery

    PubMed Central

    Muramatsu, Masahiro; Negishi, Kazuno; Tsubota, Kazuo

    2013-01-01

    Abstract Background Gait speed and sleep quality are health indices related to longevity and mortality. In the present study, we measured sleep quality, quality of life, gait speed, and visual acuity before and after cataract surgery to evaluate the efficacy of the procedure on systemic health. Methods The study was conducted on 155 patients (93 women; average age 74.8 years) undergoing cataract surgery with the implantation of a yellow soft acrylic lens. Patients were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the National Eye Institute Visual Function Questionnaire 25 (VFQ-25; vision-related quality of life) before and then 2 and 7 months after surgery. Four-meter gait speed was also determined. Results Of the 155 patients, 68 (43.9%) were classified as poor sleepers (PSQI>5.5) prior to surgery. Significant improvements were noted in sleep 2 months after surgery (p<0.05, paired t-test), but thereafter the improvements were not significant. Prior to surgery, 117 patients (77.0%) were classified as slow walkers (speed<1.0 meter/s). Gait speed increased significantly in these patients 2 months after surgery (p<0.001, paired t-test). Multiple regression analysis revealed significant correlations between the preoperative VFQ-25 score and both PSQI (p<0.05) and gait speed (p<0.001). Postoperative increases in the VFQ-25 score were positively correlated with decreases in the PSQI (p<0.05). Improvements in visual acuity were correlated with improvements in the VFQ-25 score, but not with either PSQI or gait speed. Conclusion Cataract surgery effectively improves sleep quality and slow gait speed. PMID:23145881

  10. Does Anxiety Cause Freezing of Gait in Parkinson's Disease?

    PubMed Central

    Ehgoetz Martens, Kaylena A.; Ellard, Colin G.; Almeida, Quincy J.

    2014-01-01

    Individuals with Parkinson's disease (PD) commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers) and 17 PD without freezing of gait (Non-Freezers) were instructed to walk in two virtual environments: (i) across a plank that was located on the ground (LOW), (ii) across a plank above a deep pit (HIGH). Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state). Freezers reported higher levels of anxiety compared to Non-Freezers (p<0.001) and all patients reported greater levels of anxiety when walking across the HIGH plank compared to the LOW (p<0.001). Freezers experienced significantly more freezing of gait episodes (p?=?0.013) and spent a significantly greater percentage of each trial frozen (p?=?0.005) when crossing the HIGH plank. This finding was even more pronounced when comparing Freezers in their OFF state. Freezers also had greater step length variability in the HIGH compared to the LOW condition, while the step length variability in Non-Freezers did not change. In conclusion, this was the first study to directly compare freezing of gait in anxious and non-anxious situations. These results present strong evidence that anxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD. PMID:25250691

  11. Perception of gait patterns that deviate from normal and symmetric biped locomotion

    PubMed Central

    Handži?, Ismet; Reed, Kyle B.

    2015-01-01

    This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW) model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial pathology. PMID:25774144

  12. Intrasubject repeatability of gait analysis data in normal and spastic children

    Microsoft Academic Search

    Gerhardt Steinwender; Vinay Saraph; Sabine Scheiber; Ernst Bernhard Zwick; Christiane Uitz; Karl Hackl

    2000-01-01

    Objective. To evaluate intrasubject repeatability of data obtained from computer-aided motion analysis in normal and spastic children.Design. Prospective controlled study.Background. Information from gait analysis is used in selecting therapeutic interventions for gait improvement in cerebral palsy. While there are several studies regarding repeatability of normal gait, there are no studies evaluating the repeatability of spastic gait.Methods. Forty children (20 normal,

  13. A comparative collision-based analysis of human gait

    PubMed Central

    Lee, David V.; Comanescu, Tudor N.; Butcher, Michael T.; Bertram, John E. A.

    2013-01-01

    This study compares human walking and running, and places them within the context of other mammalian gaits. We use a collision-based approach to analyse the fundamental dynamics of the centre of mass (CoM) according to three angles derived from the instantaneous force and velocity vectors. These dimensionless angles permit comparisons across gait, species and size. The collision angle ?, which is equivalent to the dimensionless mechanical cost of transport CoTmech, is found to be three times greater during running than walking of humans. This threefold difference is consistent with previous studies of walking versus trotting of quadrupeds, albeit tends to be greater in the gaits of humans and hopping bipeds than in quadrupeds. Plotting the collision angle ? together with the angles of the CoM force vector ? and velocity vector ? results in the functional grouping of bipedal and quadrupedal gaits according to their CoM dynamics—walking, galloping and ambling are distinguished as separate gaits that employ collision reduction, whereas trotting, running and hopping employ little collision reduction and represent more of a continuum that is influenced by dimensionless speed. Comparable with quadrupedal mammals, collision fraction (the ratio of actual to potential collision) is 0.51 during walking and 0.89 during running, indicating substantial collision reduction during walking, but not running, of humans. PMID:24089334

  14. Knee muscle strength in multiple sclerosis: relationship with gait characteristics.

    PubMed

    Güner, Senem; Haghar?, Sema; Inan?c?, Fatma; Alsancak, Serap; Aytek?n, Gokhan

    2015-03-01

    [Purpose] To investigate the relationship between isokinetic knee muscle strength and kinematic, kinetic and spatiotemporal gait parameters of patients with multiple sclerosis (MS). [Subjects and Methods] Twenty-nine MS patients (mean age 31.5±6.5) were investigated in this study. The isokinetic knee muscle strength and gait parameters of MS patients with moderate and severe disability, as determined by the expanded disability status scale (EDSS): EDSS=1-4.5 (n=22, moderate disability) and EDSS>4.5 (n=7, severe disability) were measured. [Results] Isokinetic knee muscle strength, kinematic, kinetic and spatiotemporal gait parameters differed between moderate (EDSS=1-4.5, n=22) and severe disability (EDSS>4.5, n=7). The correlation between each of gait speed, stride length, total range of knee joint movement and the four strength parameters (minimum and maximum quadriceps and hamstring muscle strengths) were significant for the MS group as a whole. Within subgroups, the correlation between minimum hamstring strength and total range of knee movement was significant only in group EDSS>4.5; minimum hamstring correlated with peak knee extensor moment in group EDSS=1-4.5, but at a reduced level of significance. [Conclusion] The present study revealed significant correlations between gait characteristics and isokinetic strength parameters of the quadriceps and hamstring muscles. Our study suggests that rehabilitation protocols for MS patients should include a critical strength training programme particularly for the hamstring and quadriceps muscles. PMID:25931736

  15. Robust Gait-Based Person Identification against Walking Speed Variations

    NASA Astrophysics Data System (ADS)

    Aqmar, Muhammad Rasyid; Shinoda, Koichi; Furui, Sadaoki

    Variations in walking speed have a strong impact on gait-based person identification. We propose a method that is robust against walking-speed variations. It is based on a combination of cubic higher-order local auto-correlation (CHLAC), gait silhouette-based principal component analysis (GSP), and a statistical framework using hidden Markov models (HMMs). The CHLAC features capture the within-phase spatio-temporal characteristics of each individual, the GSP features retain more shape/phase information for better gait sequence alignment, and the HMMs classify the ID of each gait even when walking speed changes nonlinearly. We compared the performance of our method with other conventional methods using five different databases, SOTON, USF-NIST, CMU-MoBo, TokyoTech A and TokyoTech B. The proposed method was equal to or better than the others when the speed did not change greatly, and it was significantly better when the speed varied across and within a gait sequence.

  16. Coexistence of Gait Disturbances and Chorea in Experimental Huntington's Disease

    PubMed Central

    Casaca-Carreira, João; Temel, Yasin; van Zelst, Marloes; Jahanshahi, Ali

    2015-01-01

    Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by an expanded CAG repeat. The clinical features are progressive motor dysfunction, cognitive deterioration, and psychiatric disturbances. Unpredictable choreic movements, among the most characteristic hallmarks, may contribute to gait disturbances and loss of balance in HD individuals. In this study, we aimed to investigate and characterize the gait abnormalities and choreic movements in a transgenic rat model of HD (tgHD). TgHD presents typical neuropathological, neurophysiological, and behavioral aspects mimicking some of the key features of human HD and is the only described experimental model for HD that exhibits choreiform movements. We used the Catwalk, with emphasis on static and dynamic gait parameters, to test the hypothesis that at symptomatic age (9 months) the dynamic measures of gait in HD are altered and coexist with choreiform movements. Our results showed that the dynamic parameters seem to be more affected than static parameters at this age in tgHD rats. The number of steps and step cycles and swing speed of the paws were increased in tgHD rat in comparison to wild-type controls. Our study demonstrates that gait abnormalities coexist with chorea rather than being caused by it. These symptoms may originate from distinct networks in the basal ganglia and downstream connections.

  17. Human odometry verifies the symmetry perspective on bipedal gaits.

    PubMed

    Turvey, M T; Harrison, Steven J; Frank, Till D; Carello, Claudia

    2012-08-01

    Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias cells) required to model them. Primary gaits are characterized by dihedral symmetry, whereas secondary gaits are characterized by a lower, cyclic symmetry. This fact was used in a test of human odometry. Results suggest that when distance is measured and reported by gaits from the same symmetry class, primary and secondary gaits are comparable. Switching symmetry classes at report compresses (primary to secondary) or inflates (secondary to primary) measured distance, with the compression and inflation equal in magnitude. Lessons are drawn from modeling the dynamics of behaviors executed in parallel (e.g., interlimb coordination) to model the dynamics of human odometry, in which the behaviors are executed sequentially. The major observations are characterized in terms of a dynamics of sequentially coupled measure and report phases, with relative velocity as an order parameter, or equilibrium state, and difference in symmetry class as an imperfection parameter, or detuning, of that dynamic. PMID:22506786

  18. Why we should study gait initiation in Parkinson's disease.

    PubMed

    Delval, A; Tard, C; Defebvre, L

    2014-01-01

    The gait initiation process is of particular interest in Parkinson's disease because it combines motor and cognitive components of movement preparation (referred to as anticipatory postural adjustments) and movement execution (the step by itself). Moreover, gait initiation in Parkinson's disease is often affected by motor blocks (a subtype of the "freezing of gait" phenomenon). Gait initiation disturbances in Parkinson's disease include delayed release of anticipatory postural adjustments, hypokinetic anticipatory postural adjustments (reduced scaling) and bradykinetic anticipatory postural adjustments (abnormal timing). The most extreme form is freezing of gait with sometimes the absence of anticipatory postural adjustments. Other phenomena can be also described in some freezing patients (such as multiple anticipatory postural adjustments, described clinically as "knee trembling"). The fact that emotion, attention, external triggers and dopaminergic drugs can all modify this motor program suggests the existence of a complex pathophysiological mechanism that involves not only locomotor networks but also cortical areas and the basal ganglia system. Abnormal coupling between standing posture and anticipatory postural adjustments and between the latter and step execution appears to be a crucial part of the pathophysiological mechanism. Although external cueing appears to be of interest, few studies have provided evidence of the efficacy of various rehabilitation methods in routine care. PMID:24502907

  19. Gait alterations to effectively reduce hip contact forces.

    PubMed

    Wesseling, Mariska; de Groote, Friedl; Meyer, Christophe; Corten, Kristoff; Simon, Jean-Pierre; Desloovere, Kaat; Jonkers, Ilse

    2015-07-01

    Patients with hip pathology present alterations in gait which have an effect on joint moments and loading. In knee osteoarthritic patients, the relation between medial knee contact forces and the knee adduction moment are currently being exploited to define gait retraining strategies to effectively reduce pain and disease progression. However, the relation between hip contact forces and joint moments has not been clearly established. Therefore, this study aims to investigate the effect of changes in hip and pelvis kinematics during gait on internal hip moments and contact forces which is calculated using muscle driven simulations. The results showed that frontal plane kinetics have the largest effect on hip contact forces. Given the high correlation between the change in hip adduction moment and contact force at initial stance (R(2) ?=?0.87), this parameter can be used to alter kinematics and predict changes in contact force. At terminal stance the hip adduction and flexion moment can be used to predict changes in contact force (R(2) ?=?0.76). Therefore, gait training that focuses on decreasing hip adduction moments, a wide base gait pattern, has the largest potential to reduce hip contact forces. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1094-1102, 2015. PMID:25676535

  20. Performance analysis for automated gait extraction and recognition in multi-camera surveillance

    Microsoft Academic Search

    Michela Goffredo; Imed Bouchrika; John N. Carter; Mark S. Nixon

    2010-01-01

    Many studies have confirmed that gait analysis can be used as a new bio- metrics. In this research, gait analysis is deployed for people identification in multi- camera surveillance scenarios. We present a new method for viewpoint independent markerless gait analysis that does not require camera calibration and works with a wide range of walking directions. These properties make the

  1. Gait synthesis of a biped robot using backpropagation through time algorithm

    Microsoft Academic Search

    Jih-Gau Juang; Chun-Shin Lin

    1996-01-01

    A neural network architecture is developed for the gait synthesis of a five-link biped walking robot. The learning scheme uses a multilayered feedforward neural network combined with a linearized inverse biped model. It can generate walking gait by giving reference trajectory which defines a desired gait in several stages. The algorithm used to train network is known as back-propagation with

  2. Fourlegged Walking Gait Control Using a Neuromorphic Chip Interfaced to a Support

    E-print Network

    Still, Susanna

    Four­legged Walking Gait Control Using a Neuromorphic Chip Interfaced to a Support Vector Learning Data acquisition program DAC Input port Walking Gait Control chip Parameter setting program SV Learning of Neuroinformatics ETH/UNI ZË?urich, Switzerland Abstract To control the walking gaits of a four­legged robot we

  3. A Novel Approach for Generalising Walking Gaits across Embodiments and Behaviours

    E-print Network

    Vijayakumar, Sethu

    . The problem is formalised using a walking phase model, and the nullspace learning method is used to generaliseA Novel Approach for Generalising Walking Gaits across Embodiments and Behaviours Hsiu-Chin Lin1 of generalising walking gaits across different subjects and behaviours. Walking gaits are a result of complex

  4. Gait Pattern Differences between Children with Mild Scoliosis and Children with Unilateral Cerebral Palsy

    PubMed Central

    Domagalska-Szopa, Ma?gorzata; Szopa, Andrzej

    2014-01-01

    This study was conducted to investigate the effects of asymmetrical body posture alone, i.e., the effects seen in children with mild scoliosis, vs. the effects of body posture control impairment, i.e., those seen in children with unilateral cerebral palsy on gait patterns. Three-dimensional instrumented gait analysis (3DGA) was conducted in 45 children with hemiplegia and 51 children with mild scoliosis. All the children were able to walk without assistance devices. A set of 35 selected spatiotemporal gait and kinematics parameters were evaluated when subjects walked on a treadmill. A cluster analysis revealed 3 different gait patterns: a scoliotic gait pattern and 2 different hemiplegic gait patterns. The results showed that the discrepancy in gait patterns was not simply a lower limb kinematic deviation in the sagittal plane, as expected. Additional altered kinematics, such as pelvic misorientation in the coronal plane in both the stance and swing phases and inadequate stance phase hip ad/abduction, which resulted from postural pattern features, were distinguished between the 3 gait patterns. Our study provides evidence for a strong correlation between postural and gait patterns in children with unilateral cerebral palsy. Information on differences in gait patterns may be used to improve the guidelines for early therapy for children with hemiplegia before abnormal gait patterns are fully established. The gait pathology characteristic of scoliotic children is a potential new direction for treating scoliosis that complements the standard posture and walking control therapy exercises with the use of biofeedback. PMID:25089908

  5. Automatic extraction and description of human gait models for recognition purposes

    Microsoft Academic Search

    David Cunado; Mark S. Nixon; John N. Carter

    2003-01-01

    Using gait as a biometric is of emerging interest. We describe a new model-based moving feature extraction analysis is presented that automatically extracts and describes human gait for recognition. The gait signature is extracted directly from the evidence gathering process. This is possible by using a Fourier series to describe the motion of the upper leg and apply temporal evidence

  6. Evaluation of an ambulatory system for gait analysis in hip osteoarthritis and after total hip replacement

    Microsoft Academic Search

    K Aminian; C Trevisan; B Najafi; H Dejnabadi; C Frigo; E Pavan; A Telonio; F Cerati; E. C Marinoni; Ph Robert; P.-F Leyvraz

    2004-01-01

    Spatial and temporal parameters of gait have clinical relevance in the assessment of motor pathologies, particularly in orthopaedics. A new gait analysis system is proposed which consists of (a) an ambulatory device (Physilog®) including a set of miniature gyroscopes and a portable datalogger, and (b) an algorithm for gait analysis. The aim of this study was the validation of this

  7. JOINT GAIT-CADENCE ANALYSIS FOR HUMAN IDENTIFICATION USING ELAS-TIC SHAPE FRAMEWORK

    E-print Network

    Srivastava, Anuj

    JOINT GAIT-CADENCE ANALYSIS FOR HUMAN IDENTIFICATION USING ELAS- TIC SHAPE FRAMEWORK David Kaziska Key Words: Biometrics; Gait recognition; Statistical shape analysis; Shape classification; Statistics on shape manifolds. ABSTRACT In this work we perform human identification by gait recognition where

  8. Baseline Results for the Challenge Problem of Human ID Using Gait Analysis P. Jonathon Phillips

    E-print Network

    Sarkar, Sudeep

    Baseline Results for the Challenge Problem of Human ID Using Gait Analysis P. Jonathon Phillips]). To assist the advancement of gait analysis, we introduce the HumanID challenge problem. We describe the data gait captured on video has become a challenge problem in computer vision. However

  9. Efficacy of clinical gait analysis: A systematic review Tishya A.L. Wren a,b,

    E-print Network

    Valero-Cuevas, Francisco

    Review Efficacy of clinical gait analysis: A systematic review Tishya A.L. Wren a,b, *, George E analysis in clinical care remains controversial. Proponents argue that gait analysis provides important, although gait analysis is a useful tool for research, as a clinical tool it adds unnecessary cost without

  10. Robust Gait Recognition Based on Procrustes Shape Analysis of Pairwise Configuration

    E-print Network

    New South Wales, University of

    Robust Gait Recognition Based on Procrustes Shape Analysis of Pairwise Configuration Worapan further developed Procrustes Shape Analysis (PSA) for robust gait recognition. As a result, a significant in many literatures to extract the signature of gait sequence captured from complete walking cycle

  11. Performance Analysis of Time-Distance Gait Parameters under Different Speeds

    E-print Network

    Haro, Antonio

    Performance Analysis of Time-Distance Gait Parameters under Different Speeds Rawesak Tanawongsuwan using 3D movement analysis system. Analyzing gait data in this aspect allows (without much concern about-0280 USA {tee, afb}@cc.gatech.edu Abstract. This paper explores gait recognition for various walking speeds

  12. Gait Analysis for Six-Legged Robots Josep M. Porta and Enric Celaya

    E-print Network

    Portland State University

    Gait Analysis for Six-Legged Robots Josep M. Porta and Enric Celaya Institut de Robotica i@iri.upc.es Abstract We present a general method for the analysis of the gaits used by a six-legged robot inde are evaluated in a rather subjective way. We present a general method for the analysis of the gait of a six

  13. A Review on Feature Extraction & Classification Techniques for Biosignal Processing (Part V: Gait Signal)

    Microsoft Academic Search

    Emran Mohd Tamil; M. H. Noor; Z. Razak; N. M. Noor; A. M. Tamil

    This paper concentrates on Gait signal processing with the emphasis on Parkinsons’s Disease diagnosis. Gait is a novel biometric\\u000a intended to recognize human from their walking pattern. This paper discussed in general about feature extraction and classification\\u000a for Gait application. Among the factor discussed and analysed include the techniques advantages, performance and drawbacks.

  14. Tracking of Thigh Flexion Angle during Gait Cycles in an Ambulatory Activity Monitoring Sensor Network1)

    Microsoft Academic Search

    DONG Liang; WU Jian-Kang; BAO Xiao-Ming; XIAO Wen-Dong

    An accelerometry-based gait analysis approach via the platform of sensor network is reported in this paper. The hardware units of the sensor network are wearable accelerometers that are attached at the limbs of human body. For the specific task of gait analysis, flexion angles of the thighs during gait cycles are computed. A Kalman filter is designed to estimate the

  15. Responsiveness and predictability of gait speed and other disability measures in acute stroke

    Microsoft Academic Search

    Nancy M. Salbach; Nancy E. Mayo; Johanne Higgins; Sara Ahmed; Lois E. Finch; Carol L. Richards

    2001-01-01

    Salbach NM, Mayo NE, Higgins J, Ahmed S, Finch LE, Richards CL. Responsiveness and predictability of gait speed and other disability measures in acute stroke. Arch Phys Med Rehabil 2001;82;1204-12. Objectives: To identify the most responsive method of measuring gait speed, to estimate the responsiveness of other outcome measures, and to determine whether gait speed predicts discharge destination in acute

  16. Investigating Gait Recognition in the Short-Wave Infrared (SWIR) Spectrum: Dataset and Challenges

    E-print Network

    Ross, Arun Abraham

    Investigating Gait Recognition in the Short-Wave Infrared (SWIR) Spectrum: Dataset and Challenges piqued interest in performing gait recognition in other spectral bands such as short-wave infrared (SWIR of performing gait recognition in the SWIR spectrum by first assembling a dataset, referred to as the WVU

  17. Nonlinear dynamical model of human gait Bruce J. West1,2,3

    E-print Network

    Scafetta, Nicola

    systems, allow for neurons within an assembly to become enslaved to a single rhythmic muscular activity dynamical model of the human gait control system in a variety of gait regimes. The stride-interval time system is coupled to the motocontrol system, and together they control the locomotion of the gait cycle

  18. Biomechanical gait alterations independent of speed in the healthy elderly: Evidence for specific limiting impairments

    Microsoft Academic Search

    D. Casey Kerrigan; Mary K. Todd; Ugo Della Croce; Lewis A. Lipsitz; James J. Collins

    1998-01-01

    Objectives: It is not known whether changes in the biomechanics of elderly gait are related to aging per se, or to reduced walking speed in this population. The goals of the present study were to identify specific biomechanical changes, independent of speed, that might impair gait performance in healthy older people by identifying age-associated changes in the biomechanics of gait,

  19. Ball Bearing Mechanics

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    Load-deflection relationships for different types of elliptical contacts such as those found in a ball bearing are developed. Simplified expressions that allow quick calculations of deformation to be made simply from a knowledge of the applied load, the material properties, and the geometry of the contacting elements are presented. Ball bearings subjected to radial, thrust and combined ball loads are analyzed. A design criterion for fatigue life of ball bearings is developed. The section of a satisfactory lubricant, as well as describing systems that provide a constant flow of lubricant to the contact, is considered.

  20. The Polar Bear Tracker

    NSDL National Science Digital Library

    This new Web site from the World Wildlife Fund (WWF) International explores how polar bears are affected by global warming. Data on the movements of two radio-collared bears can be viewed, along with the ice status, through a series of online maps. This is an interesting site with valuable information and a nice balance of maps, photos, and text. The animation of the polar bear tracking data is a really neat feature, but is best viewed by advancing through the stages manually because the rapid speed of the film makes it difficult to comprehend.

  1. Weight Control

    MedlinePLUS

    ... weight, the calories you eat must equal the energy you burn. To lose weight, you must use more calories than you eat. A weight-control strategy might include Choosing low-fat, low-calorie foods Eating smaller portions Drinking water instead of sugary drinks Being physically active Eating ...

  2. Extracting gait parameters from raw electronic walkway data.

    PubMed

    Dias, André; Gorzelniak, Lukas; Döring, Angela; Hartvigsen, Gunnar; Horsch, Alexander

    2011-01-01

    Spatiotemporal gait parameters are very important for the detection of gait impairments and associated conditions. Current methods to measure such parameters, e.g. electronic walkways or force plates, are costly and can only be used in a laboratory. The new generation of raw data accelerometers might be a cheap and flexible alternative. We conducted a small feasibility study with 50 subjects from the KORA-Age project exploring the output of GAITRite and Actigraph GT3X. We open-sourced a package to extract and process raw data from GAITRite. The most promising location for the accelerometer seems to be at the ankle. The use of accelerometers showed to be simple and reliable, indicating that they can be used in daily life to extract gait parameters. PMID:21893789

  3. A maladaptive gait abnormality in patients with lumbar spinal stenosis.

    PubMed

    Kerrigan, D C; Ehrenthal, S R

    1996-01-01

    A maladaptive pattern of abnormally increased anterior pelvic tilt during gait was documented using quantitative gait analysis in two patients presenting with lumbar spinal stenosis. Both patients also had, by physical examination, mild bilateral hip flexion contracture impairments which mayor may not have been directly related to the spinal stenosis. There is no literature to date supporting the presence of either hip flexion contractures or excessive anterior pelvic tilt during gait in patients with lumbar spinal stenosis. The excessive anterior pelvic tilt present in these patients was presumably a compensation for the hip flexion contractures to achieve reasonable step lengths. Increased anterior pelvic tilt induces increased hyperextension of the lumbosacral spine, which in a patient with spinal stenosis, could cause pain and lead to further spinal nerve impingement. Since hip flexion contracture impairments are amenable to stretching, their presence should be especially pursued in patients with spinal stenosis. PMID:24572555

  4. Telemetry experiments with a hibernating black bear

    NASA Technical Reports Server (NTRS)

    Craighead, J. J.; Varney, J. R.; Sumner, J. S.; Craighead, F. C., Jr.

    1972-01-01

    The objectives of this research were to develop and test telemetry equipment suitable for monitoring physiological parameters and activity of a hibernating bear in its den, to monitor this data and other environmental information with the Nimbus 3 IRLS data collection system, and to refine immobilizing, handling, and other techniques required in future work with wild bears under natural conditions. A temperature-telemetering transmitter was implanted in the abdominal cavity of a captive black bear and body temperature data was recorded continuously during a 3 month hibernation period. Body temperatures ranging between 37.5 and 31.8 C were observed. Body temperature and overall activity were influenced by disturbances and ambient den temperature. Nychthemeral temperature changes were not noticable. A load cell weight recording device was tested for determining weight loss during hibernation. Monitoring of data by satellite was not attempted. The implanted transmitter was removed and the bear was released with a radiolocation collar at the conclusion of the experiment.

  5. Influence of pressure-relief insoles developed for loaded gait (backpackers and obese people) on plantar pressure distribution and ground reaction forces.

    PubMed

    Peduzzi de Castro, Marcelo; Abreu, Sofia; Pinto, Viviana; Santos, Rubim; Machado, Leandro; Vaz, Mario; Vilas-Boas, João Paulo

    2014-07-01

    The aims of this study were to test the effects of two pressure relief insoles developed for backpackers and obese people on the ground reaction forces (GRF) and plantar pressure peaks during gait; and to compare the GRF and plantar pressures among normal-weight, backpackers, and obese participants. Based on GRF, plantar pressures, and finite element analysis two insoles were manufactured: flat cork-based insole with (i) corkgel in the rearfoot and forefoot (SLS1) and with (ii) poron foam in the great toe and lateral forefoot (SLS2). Gait data were recorded from 21 normal-weight/backpackers and 10 obese participants. The SLS1 did not influence the GRF, but it relieved the pressure peaks for both backpackers and obese participants. In SLS2 the load acceptance GRF peak was lower; however, it did not reduce the plantar pressure peaks. The GRF and plantar pressure gait pattern were different among the normal-weight, backpackers and obese participants. PMID:24468683

  6. Investigation of Pressurized Wave Bearings

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Dimofte, Florin

    2003-01-01

    The wave bearing has been pioneered and developed by Dr. Dimofte over the past several years. This bearing will be the main focus of this research. It is believed that the wave bearing offers a number of advantages over the foil bearing, which is the bearing that NASA is currently pursuing for turbomachinery applications. The wave bearing is basically a journal bearing whose film thickness varies around the circumference approximately sinusoidally, with usually 3 or 4 waves. Being a rigid geometry bearing, it provides precise control of shaft centerlines. The wave profile also provides good load capacity and makes the bearing very stable. Manufacturing techniques have been devised that should allow the production of wave bearings almost as cheaply as conventional full-circular bearings.

  7. PCs and Polar Bears

    NSDL National Science Digital Library

    Jessica Fries-Gaither

    2011-01-01

    This article looks at the growing energy consumption from consumer electronics and the increases it may cause in greenhouse gases and global warming. The article appears in the free, online magazine Beyond Penguins and Polar Bears.

  8. Subtle gait changes in patients with REM sleep behavior disorder.

    PubMed

    McDade, Eric M; Boot, Brendon P; Christianson, Teresa J H; Pankratz, V Shane; Boeve, Bradley F; Ferman, Tanis J; Bieniek, Kevin; Hollman, John H; Roberts, Rosebud O; Mielke, Michelle M; Knopman, David S; Petersen, Ronald C

    2013-11-01

    Many people with rapid eye movement (REM) sleep behavior disorder (RBD) have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. Because gait disorders are common in the synucleinopathies, early abnormalities in gait in those with RBD could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. We identified 42 probable RBD subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence, and stride dynamics with an automated gait analysis system. Cases and controls were similar in age (79.9?±?4.7 and 80.1?±?4.7, P?=?0.74), Unified Parkinson's Disease Rating Scale Part III (UPDRS) score (3.3?±?5.5 and 1.9?±?4.1, P?=?0.21) and Mini-Mental State Examination scores (27.2?±?1.9 and 27.7?±?1.6, P?=?0.10). A diagnosis of probable RBD was associated with decreased velocity (-7.9 cm/s; 95% confidence interval [CI], -13.8 to -2.0; P?gait changes prior to overt clinical parkinsonism. Diagnosis of probable RBD supplemented by gait analysis may help as a screening tool for disorders of ?-synuclein. PMID:24130124

  9. Subtle gait changes in patients with REM Behavior Disorder

    PubMed Central

    McDade, Eric M; Boot, Brendon P.; Christianson, Teresa JH; Pankratz, V. Shane; Boeve, Bradley F; Ferman, Tanis J.; Bieniek, Kevin; Hollman, John H; Roberts, Rosebud O; Mielke, Michelle M; Knopman, David S.; Petersen, Ronald C.

    2013-01-01

    Background Many people with REM sleep behavior disorder have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. As gait disorders are common in the synucleinopathies, early abnormalities in gait in those with REM sleep behavior disorder could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. Methods We identified 42 probable REM sleep behavior disorder subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence and stride dynamics with an automated gait analysis system. Results Cases and controls were similar in age (79.9 ± 4.7 & 80.1 ± 4.7, p= 0.74), UPDRS score (3.3 ± 5.5 & 1.9 ± 4.1, p=0.21) and Mini-Mental State Examination scores (27.2 ± 1.9 & 27.7 ± 1.6, p=0.10). A diagnosis of probable REM sleep behavior disorder was associated with decreased velocity (?7.9 cm/sec, 95%CI ?13.8 to ?2.0, p<0.01), cadence (?4.4 steps/min, 95%CI ?7.6 to ?1.3, p<0.01), and significantly increased double limb support variability (30%, 95%CI 6 – 60, p=0.01), greater stride time variability (29%, 95%CI 2 – 63, p=0.03) and swing time variability (46%, 95%CI 15 – 84, p<0.01). Conclusions Probable REM sleep behavior disorder is associated with subtle gait changes prior to overt clinical parkinsonism. Diagnosis of probable REM sleep behavior disorder supplemented by gait analysis may help as a screening tool for disorders of ?-synuclein. PMID:24130124

  10. Classification of gait disturbances: distinguishing between continuous and episodic changes

    PubMed Central

    Giladi, Nir; Horak, Fay B; Hausdorff, Jeffrey M.

    2013-01-01

    The increased awareness of the importance of gait and postural control to quality of life and functional independence has led many research groups to study the patho-physiology, epidemiology, clinical, and therapeutic aspects of these motor functions. In recognition of the increased awareness of the significance of this topic, the Movement Disorders Journal is devoting this entire issue to gait and postural control. Leading research groups provide critical reviews of the current knowledge and propose future directions for this evolving field. The results of a large randomized controlled trial designed to reduce falls and improve mobility in people with Parkinson’s disease is also included in this issue. The intensive work in this area throughout the world has created an urgent need for a unified language. Because gait and postural disturbances are so common, the clinical classification should be clear, straightforward and simple to use. As an introduction to this special issue, we propose a new clinically based classification scheme that is organized according to the dominant observed disturbance, while taking into an account the results of a basic neurological exam. The proposed classification differentiates between continuous and episodic gait disturbances since this subdivision has important ramifications from the functional, prognostic and mechanistic perspectives. We anticipate that research into gait and postural control will continue to flourish over the next decade as the search for new ways of promoting mobility and independence aims to keep up with the exponentially growing population of aging older adults. Hopefully, this new classification scheme and the papers focusing on gait and postural control in this special issue of the Movement Disorders Journal will help to facilitate future investigations in this exciting and rapidly growing area. PMID:24132835

  11. Gait and balance in adults with Friedreich's ataxia.

    PubMed

    Stephenson, Jeannie; Zesiewicz, Theresa; Gooch, Clifton; Wecker, Lynn; Sullivan, Kelly; Jahan, Israt; Kim, Seok Hun

    2015-02-01

    Friedreich's ataxia (FA) is an autosomal recessive, neurodegenerative disease characterized by progressive muscle weakness and sensory loss, balance deficits, and gait ataxia. Gait and balance impairments become worse as the disease progresses, but limited research has quantitatively assessed these deficits in adults with FA. The purpose of this study was to analyze gait and balance in this population and investigate the relationship between these variables. Eight subjects with genetically confirmed FA (29.4±9.0 years) and eight healthy, matched control subjects (29.6±9.1 years) participated in this study. Spatiotemporal gait parameters were examined using the GAITRite Walkway System while balance was examined utilizing the Biodex Balance System SD and the Berg Balance Scale (BBS). The FA group exhibited approximately 50% slower gait velocity and 32% shorter step and stride lengths compared to the control group for both comfortable and fast walking (p<0.001). Further, stride length variability in the FA group was 3.4 and 2.7 times that of controls for comfortable and fast walking, respectively (p<0.01). Subjects with FA took 72% longer to complete the limits of stability (LOS) test and attained an overall directional control score that was 50% that of controls (p<0.05). Lastly, age at FA symptom onset correlated with stride length variability during fast walking (p<0.05), and BBS and LOS test scores correlated with stride length variability during both comfortable and fast walking (p<0.05). Results demonstrate that adults with FA have significantly impaired gait and balance and several measures of these impairments are correlated. PMID:25662043

  12. Gait improvement surgery in ambulatory children with diplegic cerebral palsy.

    PubMed

    Terjesen, Terje; Lofterød, Bjørn; Skaaret, Ingrid

    2015-08-01

    Background and purpose - Instrumented 3-D gait analyses (GA) in children with cerebral palsy (CP) have shown improved gait function 1 year postoperatively. Using GA, we assessed the outcome after 5 years and evaluated parental satisfaction with the surgery and the need for additional surgery. Patients and methods - 34 ambulatory children with spastic diplegia had preoperative GA. Based on this GA, the children underwent 195 orthopedic procedures on their lower limbs at a mean age of 11.6 (6-19) years. On average, 5.7 (1-11) procedures per child were performed. Outcome measures were evaluation of gait quality using the gait profile score (GPS) and selected kinematic parameters, functional level using the functional mobility scale (FMS), and the degree of parental satisfaction. Results - The mean GPS improved from 20.7° (95% CI: 19-23) preoperatively to 15.4° (95% CI: 14-17) 5 years postoperatively. There was no significant change in GPS between 1 and 5 years. The individual kinematic parameters at the ankle, knee, and hip improved statistically significantly, as did gait function (FMS). The mean parental satisfaction, on a scale from 0 to 10, was 7.7 (2-10) points. There was a need for additional surgical procedures in 14 children; this was more frequent in those who had the index operation at an early age. Interpretation - The main finding was that orthopedic surgery based on preoperative GA gave marked improvements in gait function and quality, which were stable over a 5-year period. Nevertheless, additional orthopedic procedures were necessary in almost half of the children and further follow-up with GA for more than 1 year postoperatively is recommended in children with risk factors for such surgery. PMID:25637100

  13. Gear bearing drive

    NASA Technical Reports Server (NTRS)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  14. Detecting Walking Gait Impairment with an Ear-worn Sensor Louis Atallah, Benny Lo, Guang-Zhong Yang

    E-print Network

    Atallah, Louis

    -- This paper investigates an ear worn sensor for the development of a gait analysis framework. Instead before pattern classification can significantly improve the proposed gait analysis framework. Keywords: wearable sensors, gait, wavelet analysis. I. INTRODUCTION Features that can quantify human gait play

  15. Visualisation of gait data with Kohonen self-organising neural maps Gabor Barton a,*, Adrian Lees a

    E-print Network

    Lisboa, Paulo

    neural network . 1. Introduction The contribution of instrumented gait analysis to clinical decision of gait analysis improves outcomes [2], there is evidence to suggest that gait analysis alters decision to the first limitation, a gait analysis report is interpreted by different experts in various ways [6

  16. A floor sensor system for gait recognition Lee Middleton, Alex A. Buss, Alex I. Bazin, and Mark S. Nixon,

    E-print Network

    contained within human gait[4, 2]. The aim of this work is to aid existing studies into gait analysis the need for video analysis. Furthermore, it allows an opportunity to study gait in a way that cannot be performed with video alone. The method for gait analysis we propose is similar in purpose to that of [3] who

  17. A Layered Deformable Model for Gait Analysis Haiping Lu, K.N. Plataniotis and A.N. Venetsanopoulos

    E-print Network

    Plataniotis, Konstantinos N.

    A Layered Deformable Model for Gait Analysis Haiping Lu, K.N. Plataniotis and A.N. Venetsanopoulos In this paper, a layered deformable model (LDM) is proposed for human body pose recovery in gait analysis body model is proposed for gait analysis and model-based gait recogni- tion. This model is called

  18. Modeling the Reliability of Ball Bearings

    NSDL National Science Digital Library

    Caroni, Chrys

    The data, created by Chrys Caroni of the National Technical University of Athens, presented in this article refer to the reliability of ball bearings in manufacturing. The data was originally published by "Lieblein and Zelen" and contains 210 observations. Rather than exploring the data to obtain a multiple linear regression solution, a theoretically derived equation is given and the data is used to test it. Some of the key concepts includes: failure times, percentiles and weighted least squares.

  19. Load responsive hydrodynamic bearing

    DOEpatents

    Kalsi, Manmohan S. (Houston, TX); Somogyi, Dezso (Sugar Land, TX); Dietle, Lannie L. (Stafford, TX)

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  20. Stroke Survivors’ Gait Adaptations to a Powered Ankle Foot Orthosis

    PubMed Central

    Ward, Jeffrey; Sugar, Thomas; Boehler, Alexander; Standeven, John; Engsberg, Jack R.

    2014-01-01

    Background and Purpose Stroke is the leading cause of long term disability in the United States, and for many it causes loss of gait function. The purpose of this research is to examine stroke survivors’ gait adaptations to training on the Powered Ankle Foot Orthosis (PAFO). Of particular interest is the stroke survivors’ ability to learn how to store and release energy properly while using the device. The PAFO utilizes robotic tendon technology and supports motion with a single degree of freedom, ankle rotation in the sagittal plane. This actuator comprises a motor and series spring. The user interacts with the output side of the spring while the robot controls the input side of the spring such that typical able body ankle moments would be generated, assuming able body ankle kinematics are seen at the output side of the spring. Methods Three individuals post-stroke participated in a three week training protocol. Outcome measures (temporal, kinematic, and kinetic) were derived from robot sensors and recorded for every step. These data are used to evaluate each stroke survivor’s adaptations to robotic gait assistance. The robot was worn only on the paretic ankle. For validation of the kinematic results, motion capture data were collected on the third subject. Results All subjects showed increased cadence, ankle range of motion, and power generation capabilities. Additionally, all subjects were able to achieve a larger power output than power input from the robot. Motion capture data collected from subject three validated the robot sensor kinematic data on the affected side, but also demonstrated an unexpected gait adaptation on the unaffected ankle. Conclusions Sensors on the gait assisting robot provide large volumes of valuable information on how gait parameters change over time. We have developed key gait evaluation metrics based on the available robot sensor information that may be useful to future researchers. All subjects adapted their gait to the robotic assistance, and many of their key metrics moved closer to typical able body values. This suggests that each subject learned to utilize the assistive moments generated by the robot, despite having no predefined ankle trajectory input from the robot. The security of being harnessed on the treadmill led to more dramatic and favorable results. PMID:25339789

  1. [Gait, balance and muscle assessment in older adults].

    PubMed

    Hars, M; Trombetti, A

    2013-06-12

    Deficits in gait, balance, and maximal and explosive force production in older adults are associated with an increased risk of falls and multiple adverse health outcomes (e.g., dependence, institutionalization and death). Assessment of gait, balance and muscle performances may have important implications for the screening and management of at-risk patients, and the development of targeted interventions. The present article provides a brief overview of available assessment methods, including validated clinical tests suitable for daily practice, and more complex instrumented assessments, recommended for clinical trials or longitudinal studies. PMID:23821845

  2. The "eye of the tiger" sign in pure akinesia with gait freezing.

    PubMed

    Erro, Roberto; Amboni, Marianna; Vitale, Carmine; Longo, Katia; Rocco, Mariangela; Russo, Carmela; Pappatà, Sabina; Brunetti, Arturo; Barone, Paolo

    2011-08-01

    The "eye of the tiger" is a neuroradiologic sign due to iron deposition in the globus pallidus: it appears as diffuse low signal intensity with a central area of high signal intensity confined to the globus pallidus. The "eye of the tiger" sign has been associated with neurodegeneration with brain iron accumulation type 1 (NBIA1), a condition caused by mutations in the gene encoding pantothenate kinase 2 (PANK2). However, the specificity of this neuroradiologic sign has been already challenged and it has been described in other neurodegenerative diseases. Here, we report the first case of a patient suffering from pure akinesia with gait freezing with the "eye of the tiger" sign in T2-weighted MRI sequences. All clinical, laboratory and radiologic data excluded other diagnosis and genetic testing excluded PANK2 mutations suggesting that the "eye of the tiger" is not specific for NBIA1 and may also occur in other movement disorders. PMID:21544665

  3. Simulation of Rolling Element Bearings

    Microsoft Academic Search

    Lars-Erik Stacke; Dag Fritzson

    Rolling bearings are high precision, low cost machine elements, used in all kinds of rotat- ing machinery. Simulations of rolling bear- ings bring increased understanding of their dy- namic behaviour, and shortens product develop- ment time. A rolling bearing simulation model called BEAST (BEAring Simulation Tool), has been developed by SKF. Due to the high demands on contact geometry description

  4. Simple modeling of hydrostatic bearings

    NASA Astrophysics Data System (ADS)

    Hull, Charlie

    2014-07-01

    Hydrostatic bearings are a key component for many large telescopes due to their high load bearing capacity, stiffness and low friction. A simple technique is presented to model these bearings to understand the effects of geometry, oil viscosity, flow control, temperature, etc. on the bearings behavior.

  5. DC Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    A magnetic-bearing-supported shaft may have a number of concentricity and alignment problems. One of these involves the relationship of the position sensors, the centerline of the backup bearings, and the magnetic center of the magnetic bearings. For magnetic bearings with permanent magnet biasing, the average control current for a given control axis that is not bearing the shaft weight will be minimized if the shaft is centered, on average over a revolution, at the magnetic center of the bearings. That position may not yield zero sensor output or center the shaft in the backup bearing clearance. The desired shaft position that gives zero average current can be achieved if a simple additional term is added to the control law. Suppose that the instantaneous control currents from each bearing are available from measurements and can be input into the control computer. If each control current is integrated with a very small rate of accumulation and the result is added to the control output, the shaft will gradually move to a position where the control current averages to zero over many revolutions. This will occur regardless of any offsets of the position sensor inputs. At that position, the average control effort is minimized in comparison to other possible locations of the shaft. Nonlinearities of the magnetic bearing are minimized at that location as well.

  6. Cryostatless high temperature supercurrent bearings for rocket engine turbopumps

    NASA Technical Reports Server (NTRS)

    Rao, Dantam K.; Dill, James F.

    1989-01-01

    The rocket engine systems examined include SSME, ALS, and CTV systems. The liquid hydrogen turbopumps in the SSME and ALS vehicle systems are identified as potentially attractive candidates for development of Supercurrent Bearings since the temperatures around the bearings is about 30 K, which is considerably lower than the 95 K transition temperatures of HTS materials. At these temperatures, the current HTS materials are shown to be capable of developing significantly higher current densities. This higher current density capability makes the development of supercurrent bearings for rocket engines an attractive proposition. These supercurrent bearings are also shown to offer significant advantages over conventional bearings used in rocket engines. They can increase the life and reliability over rolling element bearings because of noncontact operation. They offer lower power loss over conventional fluid film bearings. Compared to conventional magnetic bearings, they can reduce the weight of controllers significantly, and require lower power because of the use of persistent currents. In addition, four technology areas that require further attention have been identified. These are: Supercurrent Bearing Conceptual Design Verification; HTS Magnet Fabrication and Testing; Cryosensors and Controller Development; and Rocket Engine Environmental Compatibility Testing.

  7. The novel quantitative technique for assessment of gait symmetry using advanced statistical learning algorithm.

    PubMed

    Wu, Jianning; Wu, Bin

    2015-01-01

    The accurate identification of gait asymmetry is very beneficial to the assessment of at-risk gait in the clinical applications. This paper investigated the application of classification method based on statistical learning algorithm to quantify gait symmetry based on the assumption that the degree of intrinsic change in dynamical system of gait is associated with the different statistical distributions between gait variables from left-right side of lower limbs; that is, the discrimination of small difference of similarity between lower limbs is considered the reorganization of their different probability distribution. The kinetic gait data of 60 participants were recorded using a strain gauge force platform during normal walking. The classification method is designed based on advanced statistical learning algorithm such as support vector machine algorithm for binary classification and is adopted to quantitatively evaluate gait symmetry. The experiment results showed that the proposed method could capture more intrinsic dynamic information hidden in gait variables and recognize the right-left gait patterns with superior generalization performance. Moreover, our proposed techniques could identify the small significant difference between lower limbs when compared to the traditional symmetry index method for gait. The proposed algorithm would become an effective tool for early identification of the elderly gait asymmetry in the clinical diagnosis. PMID:25705672

  8. Models of central pattern generators for quadruped locomotion. II. Secondary gaits.

    PubMed

    Buono, P L

    2001-04-01

    We continue the analysis of the network of symmetrically coupled cells modeling central pattern generators (CPG) for quadruped locomotion proposed by Golubitsky, Stewart, Buono and Collins by studying secondary gaits. Secondary gaits are modeled by output signals from the CPG where each cell emits one of two different output signals along with exact phase shifts. Examples of secondary gaits are transverse gallop, rotary gallop, and canter. We classify secondary gaits that bifurcate when the Poincaré map of a primary gait has a real eigenvalue crossing the unit circle. In particular, we show that periodic solutions modeling transverse gallop and rotary gallop bifurcate from primary gaits. Moreover, we find gaits from period-doubling bifurcations and analyze plausible footfall patterns. Numerical simulations are performed using the Morris-Lecar equations as cell dynamics. PMID:11374123

  9. [3-D ultrasound-assisted gait analysis of schizophrenic patients. Comparison between conventional neuroleptics and olanzapine].

    PubMed

    Putzhammer, Albert; Heindl, Bernhard; Müller, Jürgen; Broll, Karin; Pfeiff, Liane; Perfahl, Maria; Hess, Linda; Koch, Horst

    2003-05-01

    Schizophrenic disorders as well as neuroleptic treatment can affect locomotion. The study assessed the influence of neuroleptic treatment on human gait via ultrasonic topometric gait analysis. In a control sample the test system proved high test-retest-reliability. Spatial and temporal gait parameters were assessed in schizophrenic patients without neuroleptic treatment (n = 12) and under treatment with conventional neuroleptics (n = 14) and re-assessed after treatment change to the atypical neuroleptic olanzapine in a repeated measures design. After switch from conventional neuroleptics to olanzapine patients showed an increase of gait velocity (p < or = 0.01) and step length (p < or = 0.01) whereas the cadence remained stable. Significant differences between the untreated state and treatment with olanzapine were not detectable. We conclude that bipedal gait is affected by conventional neuroleptic treatment. The degree of impairment can be objectively measured by testing spatio-temporal and kinematic gait parameters via three-dimensional ultrasonic gait analysis. PMID:14509054

  10. Metabolic Cost, Mechanical Work, and Efficiency during Normal Walking in Obese and Normal-Weight Children

    ERIC Educational Resources Information Center

    Huang, Liang; Chen, Peijie; Zhuang, Jie; Zhang, Yanxin; Walt, Sharon

    2013-01-01

    Purpose: This study aimed to investigate the influence of childhood obesity on energetic cost during normal walking and to determine if obese children choose a walking strategy optimizing their gait pattern. Method: Sixteen obese children with no functional abnormalities were matched by age and gender with 16 normal-weight children. All…

  11. PRESSURE DEVELOPMENT IN SEALED CONTAINERS WITH PLUTONIUM BEARING MATERIALS

    Microsoft Academic Search

    J. Duffey; R. Livingston

    2010-01-01

    Gas generation by plutonium-bearing materials in sealed containers has been studied. The gas composition and pressure are determined over periods from months to years. The Pu-bearing materials studied represent those produced by all of the major processes used by DOE in the processing of plutonium and include the maximum amount of water (0.5% by weight) allowed by DOE's 3013 Standard.

  12. Knee bearing technology: where is technology taking us?

    PubMed

    Kester, Mark A; Herrera, Lizeth; Wang, Aiguo; Essner, Aaron

    2007-10-01

    A novel sequentially irradiated and annealed bearing material (X3), characterized for use in knee arthroplasty, has been developed. Attention was directed to mechanical strength properties, oxidation resistance, and the ability to reduce wear. Material properties such as ultimate tensile and yield strength were unaffected by the sequential cross-linking process. Elongation was reduced relative to GUR 1020 conventional polyethylene, but equivalent to that of direct compression molded 1900 material. In knee simulator testing for normal gait and stair climbing, measured wear rates for X3 polyethylene were reduced by 79% and 77% when compared to the same knee design using conventional polyethylene. Mechanical properties and wear characteristics of the X3 polyethylene were unaffected before and after exposure to accelerated aging; properties of conventional polyethylene were adversely impacted. PMID:17919587

  13. Changes in length of the plantar aponeurosis during the stance phase of gait--an in vivo dynamic fluoroscopic study.

    PubMed

    Fessel, G; Jacob, H A C; Wyss, Ch; Mittlmeier, Th; Müller-Gerbl, M; Büttner, A

    2014-12-01

    In locomotion, ligaments and muscles have been recognized to support the arch of the foot. However, it remains unclear to what extent the passive and active structures of the lower extremity support the longitudinal arch of the foot during walking. In this study, the mechanical function of the plantar aponeurosis (PA) is investigated by elongation measurements in vivo during the stance phase of gait, in combination with measurements of the mechanical properties of the PA in vitro. Fluoroscopy was used to measure the dynamic changes in PA length and the angular motion of the metatarsophalangeal joint of the first ray, measured during the stance phase (StPh) in 11 feet. Simultaneously, ground forces were measured. Additionally, four cadaver feet delivered topographic information relating to the PA, and three autopsy specimens of PA served to determine the in vitro mechanical properties of PA. The present study revealed a non-significant peak average PA shortening of 0.48% at about 32.5% StPh, followed by a significant average peak elongation of 3.6% at 77.5% StPh. This average peak elongation of 3.6% corresponds to a force of 292N, as estimated by mechanical testing of the autopsy PA specimens. Considering the maximum peak elongation measured in one volunteer of 4.8% at 76% StPh, a peak PA load of 488N might be expected. Hence, with an average body weight of 751N, as allocated to the 11 investigated feet, this maximum peak force would correspond to about 0.65×body weight. As far as we are aware, this is the first report on a dynamic fluoroscopic study of the PA in gait with an appreciable number of feet (11 feet). In conclusion, muscles contribute to support of the longitudinal arch of the foot and can possibly relax the PA during gait. The 'windlass effect' for support of the arch in this context is therefore questionable. PMID:25113063

  14. Modeling and Learning Walking Gaits of Biped Robots

    E-print Network

    Menegatti, Emanuele

    Modeling and Learning Walking Gaits of Biped Robots Matthias Hebbel, Ralf Kosse and Walter Nistico in the simulator. Finally, we present the results of a walk learning experiment which was done on a real robot. For these experiments we have developed a system which allows the robot to learn to walk fully autonomously. II

  15. Generating Arachnid Robot Gaits with Cyclic Genetic Algorithms

    E-print Network

    Parker, Gary B.

    ://www.cs.indiana.edu/hyplan/gaparker.html ABSTRACT Learning gaits for walking robots is difficult because the elements of control require repetition repeated. Although learning to actuate a single leg for a single step is not difficult, learning to walk for learning algorithms since it usually requires sequential solutions where a series of actions is continually

  16. Normalisation of gait EMGs: a re-examination

    Microsoft Academic Search

    A. M. Burden; M. Trew; V. Baltzopoulos

    2003-01-01

    The purpose of this study was to compare four different methods of normalising electromyograms (EMGs) recorded during normal gait. Comparisons were made between the amplitude, intra-individual variability and inter-individual variability of EMGs. Surface EMGs were recorded from the biceps femoris, semitendinosus, vastus lateralis and vastus medialis of ten males and two females while they walked on a treadmill at a

  17. Neural Network Gait Classification for On-Body Inertial Sensors

    Microsoft Academic Search

    Mark A. Hanson; Harry C. Powell Jr.; Adam T. Barth; John Laché Maïté Brandt-pearce; Maïté Brandt-Pearce

    2009-01-01

    Clinicians have determined that continuous ambulatory monitoring provides significant preventative and diagnostic benefit, especially to the aged population. In this paper we describe gait classification techniques based on data obtained using a new body area sensor network platform named TEMPO 3. The platform and its supporting infrastructure enable six-degrees-of-freedom inertial sensing, signal processing, and wireless transmission. The proposed signal processing

  18. Bill Goodwine and Joel Burdick Gait Controllability for Legged Robots

    E-print Network

    Goodwine, Bill

    Bill Goodwine and Joel Burdick Gait Controllability for Legged Robots Bill Goodwine Joel Burdick to the legged case, where the relevant mechanics are not smooth. #12;Bill Goodwine and Joel Burdick Introduction to a class of nonsmooth systems we call stratified. #12;Bill Goodwine and Joel Burdick Stratified Control

  19. Use of gait parameters of persons in video surveillance systems

    NASA Astrophysics Data System (ADS)

    Geradts, Zeno J.; Merlijn, Menno; de Groot, Gert; Bijhold, Jurrien

    2002-07-01

    The gait parameters of eleven subjects were evaluated to provide data for recognition purposes of subjects. Video images of these subjects were acquired in frontal, transversal, and sagittal (a plane parallel to the median of the body) view. The subjects walked by at their usual walking speed. The measured parameters were hip, knee and ankle joint angle and their time averaged values, thigh, foot and trunk angle, step length and width, cycle time and walking speed. Correlation coefficients within and between subjects for the hip, knee and ankle rotation pattern in the sagittal aspect and for the trunk rotation pattern in the transversal aspect were almost similar. (were similar or were almost identical) This implies that the intra and inter individual variance were equal. Therefore, these gait parameters could not distinguish between subjects. A simple ANOVA with a follow-up test was used to detect significant differences for the mean hip, knee and ankle joint angle, thigh angle, step length, step width, walking speed, cycle time and foot angle. The number of significant differences between subjects defined the usefulness of the gait parameter. The parameter with the most significant difference between subjects was the foot angle (64 % - 73 % of the maximal attainable significant differences), followed by the time average hip joint angle (58 %) and the step length (45 %). The other parameters scored less than 25 %, which is poor for recognition purposes. The use of gait for identification purposes it not yet possible based on this research.

  20. Use of gait parameters of persons in video surveillance systems

    Microsoft Academic Search

    Zeno J. Geradts; Menno Merlijn; Gert de Groot; Jurrien Bijhold

    2002-01-01

    The gait parameters of eleven subjects were evaluated to provide data for recognition purposes of subjects. Video images of these subjects were acquired in frontal, transversal, and sagittal (a plane parallel to the median of the body) view. The subjects walked by at their usual walking speed. The measured parameters were hip, knee and ankle joint angle and their time

  1. The Significance of Leg Mass in Modeling Quadrupedal Running Gaits

    Microsoft Academic Search

    James Schmiedeler; Robert Siston; Kenneth Waldron

    In modeling running gaits of biological and robotic quadrupeds, leg mass is often neglected. Analysis of the system angular momentum in a biological model and a robot model indicates that including leg mass is significant in capturing the roll motion in trotting and pacing. Leg mass has a more significant effect on the pitch motion in bounding and is most

  2. An Improved Method for Muscle Activation Detection During Gait

    E-print Network

    Adler, Andy

    1 An Improved Method for Muscle Activation Detection During Gait Lanyi Xu, Andy Adler School a composite electrical signal is measured of the electrical activity in the nearby muscle tissue. The early methods for detecting muscle activation were based on setting a threshold of EMG envelop amplitude

  3. Method for monitoring acceleration of the trunk during gait

    Microsoft Academic Search

    D. Villanueva; A. Trujillo; E. Fermon; E. Cardiel; P. R. Hedz

    2002-01-01

    In this study we describe the electronic instrumentation for monitoring the trajectories of the trunk of the human body during gait of healthy subjects on a treadmill. Acceleration signals were assessed using the information provided by foot pressure sensors. This system is light, compact, inexpensive, and does not provoke any discomfort to subjects during the experimental evaluation. Several clinical and

  4. Predicting peak kinematic and kinetic parameters from gait speed

    Microsoft Academic Search

    Jennifer L Lelas; Gregory J Merriman; Patrick O Riley; D. Casey Kerrigan

    2003-01-01

    Objective: The aim of this study is to assess the predictability of the relationships between gait speed and common peak sagittal plane parameters in order to provide a set of reference parameter values. Design: Lower extremity biomechanical data were collected in 64 healthy adults while walking barefoot at his\\/her comfortable walking speed, then at self-selected fast, slow and very slow

  5. Walking Gait Optimization for Accommodation of Unknown Terrain Height Variations

    E-print Network

    Grizzle, Jessy W.

    Walking Gait Optimization for Accommodation of Unknown Terrain Height Variations Brent Griffin of terrain height changes. Trajectory and control deviations are related to a nominal periodic orbit via that specifically account for trajectory and control-effort perturbations arising from a finite set of ground height

  6. 3D Tracking for Gait Characterization and Recognition

    Microsoft Academic Search

    Raquel Urtasun; Pascal Fua

    2004-01-01

    We propose an approach to gait analysis that relies on fitting 3-D temporal motion models to synchronized video sequences. These models allow us not only to track but also to recover motion parameters that can be used to recognize people and characterize their style. Because our method is robust to occlusions and insen- sitive to changes in direction of motion,

  7. Gait Analysis of Cerebral Palsy Children before and after Rhizotomy

    Microsoft Academic Search

    Christopher L. Vaughan; Barbara Berman; Loretta A. Staudt; Warwick J. Peacock

    1988-01-01

    Over the past decade, selective posterior rhizotomy has been used successfully to reduce spasticity in patients with cerebral palsy. Although clinical evaluation of these patients revealed functional improvement following surgery, more objective analysis of the outcome of this surgery was sought. Kinematic gait analysis of 14 patients with spastic cerebral palsy was performed before and after selective posterior rhizotomy. Measurements

  8. Gait analysis for human identification in frequency domain

    Microsoft Academic Search

    Shiqi Yu; Liang Wang; Weiming Hu; Tieniu Tan

    2004-01-01

    In this paper, we analyze the spatio-temporal human characteristic of moving silhouettes in frequency domain, and find key Fourier descriptors that have better discriminatory capability for recognition than the other Fourier descriptors. A large number of experimental results and analysis show that the proposed algorithm based on the key Fourier descriptors can not only greatly reduce the gait data dimensionality,

  9. Rehabilitation in limb deficiency. 1. Gait and motion analysis

    Microsoft Academic Search

    Joseph M. Czerniecki

    1996-01-01

    This self-directed learning module highlights new advances in this topic area. It is part of the chapter on rehabilitation in limb deficiency in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article discusses normal gait, the influence of prosthetic alignment on amputee function, and the effects of prosthetic components on the metabolic costs

  10. Modelling gait transition in two-legged animals

    NASA Astrophysics Data System (ADS)

    Pinto, Carla M. A.; Santos, Alexandra P.

    2011-12-01

    The study of locomotor patterns has been a major research goal in the last decades. Understanding how intralimb and interlimb coordination works out so well in animals' locomotion is a hard and challenging task. Many models have been proposed to model animal's rhythms. These models have also been applied to the control of rhythmic movements of adaptive legged robots, namely biped, quadruped and other designs. In this paper we study gait transition in a central pattern generator (CPG) model for bipeds, the 4-cells model. This model is proposed by Golubitsky, Stewart, Buono and Collins and is studied further by Pinto and Golubitsky. We briefly resume the work done by Pinto and Golubitsky. We compute numerically gait transition in the 4-cells CPG model for bipeds. We use Morris-Lecar equations and Wilson-Cowan equations as the internal dynamics for each cell. We also consider two types of coupling between the cells: diffusive and synaptic. We obtain secondary gaits by bifurcation of primary gaits, by varying the coupling strengths. Nevertheless, some bifurcating branches could not be obtained, emphasizing the fact that despite analytically those bifurcations exist, finding them is a hard task and requires variation of other parameters of the equations. We note that the type of coupling did not influence the results.

  11. Effects of hip joint centre mislocation on gait analysis results

    Microsoft Academic Search

    Rita Stagni; Alberto Leardini; Aurelio Cappozzo; Maria Grazia Benedetti; Angelo Cappello

    2000-01-01

    Methods to determine the hip joint centre (HJC) location are necessary in gait analysis. It has been demonstrated that the methods proposed in the literature involve large mislocation errors. The choice should be made according to the extent by which HJC location errors distort the estimates of angles and resultant moments at the hip and knee joints. This study aimed

  12. Are joint torques the Holy Grail of human gait analysis?

    Microsoft Academic Search

    Christopher L. Vaughan

    1996-01-01

    Despite complex control systems, human gait is characterised by smooth, regular and repeating movements. Such coordinated motion occurs as a direct result of the cyclical activation of many leg muscles. It is the tension in these muscles that serves as the direct cause of the kinematic patterns that we observe and recognise as locomotion. The challenge facing biomechanists, however, is

  13. Gait Analysis of Adult Paraplegic Rats after Spinal Cord Repair

    Microsoft Academic Search

    Henrich Cheng; Susanne Almström; Lydia Giménez-Llort; Robert Chang; Sven Ove Ögren; Barry Hoffer; Lars Olson

    1997-01-01

    This study presents a novel detailed method of analysis of rat gait and uses this method to demonstrate recovery of forward locomotion patterns in adult rats made paraplegic by surgical spinal cord transection and subjected to a novel strategy for spinal cord repair. Six normal rats were compared to five animals in which the cord was transected at T8–T9, and

  14. A Simple Computer-Television Interface System for Gait Analysis

    Microsoft Academic Search

    In-Sheng Cheng; S. H. Koozekanani; M. T. Fatehi

    1975-01-01

    A new method for analysis and recording of gait parameters is reported. This method consists of a television camera interfaced with a PDP-11\\/10 minicomputer. The TV camera picks up anatomical points of interest such as knee joint, ankle joint, etc., to which small lights are attached and the computer calculates their coordinates and joint angles as a function of time.

  15. Feasibility study on iPhone accelerometer for gait detection

    Microsoft Academic Search

    Herman K. Y. Chan; Huiru Zheng; Haiying Wang; Rachel Gawley; Mingjing Yang; Roy Sterritt

    2011-01-01

    Falls amongst the elderly is becoming a major problem with over 50% of elderly hospitalizations due to injury from fall related accidents. Healthcare expenses are dramatically rising due to growing elderly population. Many current technologies for gait analysis are laboratory-based and can incur substantial costs for the healthcare sector for treatment of falls. However utilization of alternative commercially available technologies

  16. EVOLVING HEXAPOD GAITS USING A CYCLIC GENETIC ALGORITHM

    E-print Network

    Parker, Gary B.

    as possible. In addition, learning reduces the human engineering required to develop the intricaciesEVOLVING HEXAPOD GAITS USING A CYCLIC GENETIC ALGORITHM GARY B. PARKER, DAVID W. BRAUN, AND INGO with the differences between and within robots would greatly reduce engineering calculations and increase robot

  17. Robotic harness for the field assessment of galloping gaits

    Microsoft Academic Search

    Surya P. N. Singh; Paul J. Csonka; Kenneth J. Waldron

    2007-01-01

    An important tool in clarifying various theories governing the dynamics of rapid quadrupedal gaits, such as the trot and gallop, is the measurement of body attitude. Such measurements are complicated in open field environments because of the large ranges and high data rates needed due to the speeds (7 m\\/s) and rapid shifts in dynamics present. To address this a

  18. Increased gait unsteadiness in community-dwelling elderly fallers

    NASA Technical Reports Server (NTRS)

    Hausdorff, J. M.; Edelberg, H. K.; Mitchell, S. L.; Goldberger, A. L.; Wei, J. Y.

    1997-01-01

    OBJECTIVE: To test the hypothesis that quantitative measures of gait unsteadiness are increased in community-dwelling elderly fallers. STUDY DESIGN: Retrospective, case-control study. SETTING: General community. PARTICIPANTS: Thirty-five community-dwelling elderly subjects older than 70 years of age who were capable of ambulating independently for 6 minutes were categorized as fallers (age, 82.2 +/- 4.9 yrs [mean +/- SD]; n = 18) and nonfallers (age, 76.5 +/- 4.0 yrs; n = 17) based on history; 22 young (age, 24.6 +/- 1.9 yrs), healthy subjects also participated as a second reference group. MAIN OUTCOME MEASURES: Stride-to-stride variability (standard deviation and coefficient of variation) of stride time, stance time, swing time, and percent stance time measured during a 6-minute walk. RESULTS: All measures of gait variability were significantly greater in the elderly fallers compared with both the elderly nonfallers and the young subjects (p < .0002). In contrast, walking speed of the elderly fallers was similar to that of the nonfallers. There were little or no differences in the variability measures of the elderly nonfallers compared with the young subjects. CONCLUSIONS: Stride-to-stride temporal variations of gait are relatively unchanged in community-dwelling elderly nonfallers, but are significantly increased in elderly fallers. Quantitative measurement of gait unsteadiness may be useful in assessing fall risk in the elderly.

  19. Gait phase and centre of pressure measuring system

    Microsoft Academic Search

    Dragoljub Surdilovic; Z. Jinyu; R. Bernhardt

    2004-01-01

    For the development of biped robot and artificial limb as well as for the rehabilitation of patients whose legs are injured or have difficulty in movement, a gait phase online identification and calculation of centre of pressure (CoP) system is researched. In previous researches, the force sensitive resistors were fit inside of the shoes, which were called sole sensors. However

  20. The Gait Identification Challenge Problem: Data Sets and Baseline Algorithm

    Microsoft Academic Search

    P. Jonathon Phillips; Sudeep Sarkar; Isidro Robledo Vega; Patrick Grother; Kevin W. Bowyer

    2002-01-01

    Recognition of people through gait analysis is an important research topic, with potential applications in video surveillance, tracking, and monitoring. Recognizing the importance of evaluating and comparing possible competing solutions to this problem, we previously introduced the HumanID challenge problem consisting of a set of experiments of increasing difficulty, a baseline algorithm, and a large set of video sequences (about

  1. A mechatronic analysis and synthesis of human walking gait

    Microsoft Academic Search

    Luis I. Lugo-Villeda; Antonio Frisoli; Oscar O. Sandoval Gonzalez; Massimo Bergamasco; Vicente Parra-Vega

    2009-01-01

    Human walking gait (HWG) involves concurrently complex aspects of control, signal conditioning and processing, motion capture and biomechanical analysis as well as bioelectronic instrumentation and robot control. To merge some of these concepts into a unique framework, in this paper, a computational mechatronics scheme is proposed for the analysis and synthesis of HWG based on a seven-link sagittal rigid dynamical

  2. Human walking capture and its inspiration to biped gait planning

    Microsoft Academic Search

    Zeyang Xia; Guodong Chen; Zhenzhong Jia; Jing Xiong; K. Chen

    2009-01-01

    Existing approaches to biped gait generation always need to assume appropriate parameter conditions of the walking patterns. To accomplish this, this paper aims to experimentally investigate the characteristics of the human walking, and reveal, to some extent, its balance strategies. The experimental study was carried out on a self-designed human walking testing platform, which captures the joint kinematics data and

  3. A PSO algorithm for biped gait planning using spline approximation

    Microsoft Academic Search

    Zhang Qizhi; Zhou Yali; Ge Xinsheng

    2010-01-01

    This paper discusses an optimal trajectory planning method for a compass gait biped robot. The biped robot is composed of a stance leg and a swing leg. Each step of walking locomotion is divided into two phases, i.e., the swing phase and toe collision phase. It is assumed that the toe collision is perfect plastic and occurs instantly. The motion

  4. Can Strength Training Predictably Improve Gait Kinematics? A Pilot

    E-print Network

    Delp, Scott

    and Knee Extensor Strengthening on Lower- Extremity Alignment in Cerebral Palsy Diane L. Damiano, Allison S that excessive hip and knee flexion during gait, as frequently seen in ambulatory children with cerebral palsy on the effects of hip and knee extensor strength- ening on lower-extremity align- ment in cerebral palsy. Phys

  5. Gait Analysis Using a Shoe-Integrated Wireless Sensor System

    Microsoft Academic Search

    Stacy J. Morris Bamberg; Ari Y. Benbasat; Donna M. Scarborough; David E. Krebs; Joseph A. Paradiso

    2008-01-01

    We describe a wireless wearable system that was developed to provide quantitative gait analysis outside the confines of the traditional motion laboratory. The sensor suite includes three orthogonal accelerometers, three orthogonal gyroscopes, four force sensors, two bidirectional bend sensors, two dynamic pressure sensors, as well as electric field height sensors. The \\

  6. A time-frequency classifier for human gait recognition

    NASA Astrophysics Data System (ADS)

    Mobasseri, Bijan G.; Amin, Moeness G.

    2009-05-01

    Radar has established itself as an effective all-weather, day or night sensor. Radar signals can penetrate walls and provide information on moving targets. Recently, radar has been used as an effective biometric sensor for classification of gait. The return from a coherent radar system contains a frequency offset in the carrier frequency, known as the Doppler Effect. The movements of arms and legs give rise to micro Doppler which can be clearly detailed in the time-frequency domain using traditional or modern time-frequency signal representation. In this paper we propose a gait classifier based on subspace learning using principal components analysis(PCA). The training set consists of feature vectors defined as either time or frequency snapshots taken from the spectrogram of radar backscatter. We show that gait signature is captured effectively in feature vectors. Feature vectors are then used in training a minimum distance classifier based on Mahalanobis distance metric. Results show that gait classification with high accuracy and short observation window is achievable using the proposed classifier.

  7. Nonlinear dynamics indicates aging affects variability during gait

    Microsoft Academic Search

    Ugo H. Buzzi; Nicholas Stergiou; Max J. Kurz; Patricia A. Hageman; Jack Heidel

    2003-01-01

    Objective. To investigate the nature of variability present in time series generated from gait parameters of two different age groups via a nonlinear analysis. Design. Measures of nonlinear dynamics were used to compare kinematic parameters between elderly and young females. Background. Aging may lead to changes in motor variability during walking, which may explain the large incidence of falls in

  8. Overview of Robot-Aided Gait Biofeedback and Assessment

    Microsoft Academic Search

    Robert Riener; Gery Colombo; Lars Lünenburger

    2006-01-01

    Robot-assisted gait training can increase the duration and number of training sessions, whilst reducing the number of therapists required per patient. However, robotic training without therapists lacks feedback required for patient assessment. In this paper, we present results from the literature and our research in order to provide an overview of novel human-centered strategies that enable the robot to support

  9. Ergonomy of paraplegic patients working with a reciprocating gait orthosis

    Microsoft Academic Search

    M Bernardi; I Canale; F Felici; A Macaluso; P Marchettoni; E Sproviero

    1995-01-01

    A reciprocating gait orthosis (RGO) is, among others, the most widely adopted device to restore the standing and walking capability of paraplegic patients. The aim of the present study was the evaluation of the energy demand ([Vdot ]02), and cardiopulmonary load (HR and [Vdot ]E) imposed on the subject by different working tasks while sitting in a wheelchair or standing

  10. Biomechanical Modelling of Phase Transitions for Human Gait Javier Finat

    E-print Network

    Llanos, Diego R.

    Biomechanical Modelling of Phase Transitions for Human Gait Javier Finat Dept. of Algebra, Faculty- pensatory behaviours. 2 Introduction Biomechanics has an increasing influence in medi- cal areas related to physiology, pathology and clin- ical treatment. Research in orthopaedic and injury biomechanics for disabled

  11. Early presentation of gait impairment in Wolfram Syndrome

    PubMed Central

    2012-01-01

    Background Classically characterized by early onset insulin-dependent diabetes mellitus, optic atrophy, deafness, diabetes insipidus, and neurological abnormalities, Wolfram syndrome (WFS) is also associated with atypical brainstem and cerebellar findings in the first decade of life. As such, we hypothesized that gait differences between individuals with WFS and typically developing (TD) individuals may be detectable across the course of the disease. Methods Gait was assessed for 13 individuals with WFS (min 6.4?yrs, max 25.8?yrs) and 29 age-matched, typically developing individuals (min 5.6?yrs, max 28.5?yrs) using a GAITRite ® walkway system. Velocity, cadence, step length, base of support and double support time were compared between groups. Results Across all tasks, individuals with WFS walked slower (p = 0.03), took shorter (p ? 0.001) and wider (p ? 0.001) steps and spent a greater proportion of the gait cycle in double support (p = 0.03) compared to TD individuals. Cadence did not differ between groups (p = 0.62). Across all tasks, age was significantly correlated with cadence and double support time in the TD group but only double support time was correlated with age in the WFS group and only during preferred pace forward (rs= 0.564, p = 0.045) and dual task forward walking (rs= 0.720, p = 0.006) tasks. Individuals with WFS also had a greater number of missteps during tandem walking (p ? 0.001). Within the WFS group, spatiotemporal measures of gait did not correlate with measures of visual acuity. Balance measures negatively correlated with normalized gait velocity during fast forward walking (rs = ?0.59, p = 0.03) and percent of gait cycle in double support during backward walking (rs = ?0.64, p = 0.03). Conclusions Quantifiable gait impairments can be detected in individuals with WFS earlier than previous clinical observations suggested. These impairments are not fully accounted for by the visual or balance deficits associated with WFS, and may be a reflection of early cerebellar and/or brainstem abnormalities. Effective patient-centered treatment paradigms could benefit from a more complete understanding of the progression of motor and other neurological symptom presentation in individuals with WFS. PMID:23217193

  12. Partial tooth gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  13. Radial Halbach Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2009-01-01

    Radial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Radial Halbach magnetic bearings are based on the same principle as that of axial Halbach magnetic bearings, differing in geometry as the names of these two types of bearings suggest. Both radial and axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control. Axial Halbach magnetic bearings were described in Axial Halbach Magnetic Bearings (LEW-18066-1), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 85. In the remainder of this article, the description of the principle of operation from the cited prior article is recapitulated and updated to incorporate the present radial geometry. In simplest terms, the basic principle of levitation in an axial or radial Halbach magnetic bearing is that of the repulsive electromagnetic force between (1) a moving permanent magnet and (2) an electric current induced in a stationary electrical conductor by the motion of the magnetic field. An axial or radial Halbach bearing includes multiple permanent magnets arranged in a Halbach array ("Halbach array" is defined below) in a rotor and multiple conductors in the form of wire coils in a stator, all arranged so the rotary motion produces an axial or radial repulsion that is sufficient to levitate the rotor. A basic Halbach array (see Figure 1) consists of a row of permanent magnets, each oriented so that its magnetic field is at a right angle to that of the adjacent magnet, and the right-angle turns are sequenced so as to maximize the magnitude of the magnetic flux density on one side of the row while minimizing it on the opposite side. The advantage of this configuration is that it makes it possible to approach the theoretical maximum force per unit area that could be exerted by a given amount of permanent-magnet material. The configuration is named after physicist Klaus Halbach, who conceived it for use in particle accelerators. Halbach arrays have also been studied for use in magnetic-levitation ("maglev") railroad trains. In a radial Halbach magnetic bearing, the basic Halbach arrangement is modified into a symmetrical arrangement of sector-shaped permanent magnets mounted on the outer cylindrical surface of a drum rotor (see Figure 2). The magnets are oriented to concentrate the magnetic field on their radially outermost surface. The stator coils are mounted in a stator shell surrounding the rotor.

  14. Blood Pump Bearing System

    NASA Technical Reports Server (NTRS)

    Aber, Gregory S. (Inventor)

    2000-01-01

    An apparatus is provided for a blood pump bearing system within a pump housing to support long-term highspeed rotation of a rotor with an impeller blade having a plurality of individual magnets disposed thereon to provide a small radial air gap between the magnets and a stator of less than 0.025 inches. The bearing system may be mounted within a flow straightener, diffuser, or other pump element to support the shaft of a pump rotor. The bearing system includes a zirconia shaft having a radiused end. The radiused end has a first radius selected to be about three times greater than the radius of the zirconia shaft. The radiused end of the zirconia shaft engages a flat sapphire endstone. Due to the relative hardness of these materials a flat is quickly produced during break-in on the zirconia radiused end of precisely the size necessary to support thrust loads whereupon wear substantially ceases. Due to the selection of the first radius, the change in shaft end-play during pump break-in is limited to a total desired end-play of less than about 0.010 inches. Radial loads are supported by an olive hole ring jewel that makes near line contact around the circumference of the Ir shaft to support big speed rotation with little friction. The width of olive hole ring jewel is small to allow heat to conduct through to thereby prevent heat build-up in the bearing. A void defined by the bearing elements may fill with blood that then coagulates within the void. The coagulated blood is then conformed to the shape of the bearing surfaces.

  15. Blood Pump Bearing System

    NASA Technical Reports Server (NTRS)

    Aber, Gregory S. (Inventor)

    1999-01-01

    Methods and apparatus are provided for a blood pump bearing system within a pump housing to support long-term high-speed rotation of a rotor with an impeller blade having a plurality of individual magnets disposed thereon to provide a small radial air gap between the magnets and a stator of less than 0.025 inches. The bearing system may be mounted within a flow straightener, diffuser, or other pump element to support the shaft of a pump rotor. The bearing system includes a zirconia shaft having a radiused end. The radiused end has a first radius selected to be about three times greater than the radius of the zirconia shaft. The radiused end of the zirconia shaft engages a flat sapphire endstone. Due to the relative hardness of these materials a flat is quickly produced during break-in on the zirconia radiused end of precisely the size necessary to support thrust loads whereupon wear substantially ceases. Due to the selection of the first radius, the change in shaft end-play during pump break-in is limited to a total desired end-play of less than about 0.010 inches. Radial loads are supported by an olive hole ring jewel that makes near line contact around the circumference of the shaft to support high speed rotation with little friction. The width of olive hole ring jewel is small to allow heat to conduct through to thereby prevent heat build-up in the bearing. A void defined by the bearing elements may fill with blood that then coagulates within the void. The coagulated blood is then conformed to the shape of the bearing surfaces.

  16. Weight Watcher!

    ERIC Educational Resources Information Center

    Clarke, Doug

    1990-01-01

    The author, using a weight machine in an airport lounge, varies the machine's input parameters of height and gender to generate data sets of ideal weight. These data are later used at in-service workshops and in both primary and secondary classrooms to explore patterns and make predictions. (JJK)

  17. Gait adaptations to simultaneous cognitive and mechanical constraints.

    PubMed

    Al-Yahya, Emad; Dawes, Helen; Collett, Johnathan; Howells, Ken; Izadi, Hooshang; Wade, Derick T; Cockburn, Janet

    2009-10-01

    Previous studies have shown that walking is not a purely automatic motor task but places demands on sensory and cognitive systems. We set out to investigate whether complex walking tasks, as when walking down a steeper gradient while performing a concurrent cognitive task, would demand gait adaptation beyond those required for walking under low-challenge conditions. Thirteen healthy young individuals walked at their self-selected speed on a treadmill at different inclinations (0, -5 and -10%). Gait spatio-temporal measures, pelvis angular excursion, and sacral centre of mass (CoM) motion were acquired while walking or while walking and performing a mental tracking task. Repeated-measures ANOVAs revealed that decreasing treadmill inclination from 0 to -10% resulted in significant decreased walking speed (P < 0.001), decreased stride length (P < 0.001), increased pelvis tilt (P = 0.006) and obliquity variability (P = 0.05), decreased pelvis rotation (P = 0.02), and increased anterio-posterior (A-P) CoM displacement (P = 0.015). Compared to walking alone, walking under dual-task condition resulted in increased step width (P < 0.001), and increased medio-lateral (M-L) CoM displacement (P = 0.039) regardless of inclination grade, while sagittal plane dynamics did not change. Findings suggest that gait adapts differently to cognitive and mechanical constraints; the cognitive system is more actively involved in controlling frontal than sagittal plane gait dynamics, while the reverse is true for the mechanical system. Finally, these findings suggest that gait adaptations maintain the ability to perform concurrent tasks while treadmill walking in healthy young adults. PMID:19672583

  18. A force measuring treadmill in clinical gait analysis.

    PubMed

    Dierick, Frédéric; Penta, Massimo; Renaut, David; Detrembleur, Christine

    2004-12-01

    This preliminary study presents the development and testing of an instrumented treadmill device measuring the ground reaction forces (GRFs) and the feasibility of using this force measuring treadmill (FMT) in clinical gait analysis. A commercially available treadmill was modified and fitted out with three-dimensional strain-gauge force transducers. Tests of linearity, centre of pressure position (CoP), cross talk, natural frequency, background noises, and belt speed were undertaken in order to assess the performance of the FMT. In addition, the GRFs and segmental kinematics were recorded while healthy subjects and patients walked on the FMT, in order to compute the net ankle joint moments and the body centre of mass (CMb) kinematics and mechanics. The preliminary results of technical tests were satisfactory with an error less than 10% and dynamic tests in healthy subjects corresponded to the literature. The results of patients were clearly disturbed, demonstrating the ability of the FMT to discriminate pathological gaits from normal ones. We concluded that the GRFs measurements obtained from the FMT seem valid and the clinical assessment of net joint moments and CMb kinematics and mechanics seem feasible. The FMT could be useful device for clinical research and routine gait analysis since it allows gaining some extra room and quickly collecting the GRFs during a large number of successive gait cycles and over a wide range of steady-state gait speeds. However, more work is needed in this area in order to confirm the present results, collect reference data and validate the methodology across pathologies. PMID:15531177

  19. Influence of the diversion of Bear River into Bear Lake (Utah and Idaho) on the environment of deposition of carbonate minerals

    Microsoft Academic Search

    Walter E. Dean; Richard M. Forester; Jordon Bright; Roger Y. Anderson

    2007-01-01

    Bear River, the largest river in the Great Basin, had some of its flow diverted into Bear Lake through a series of canals constructed between 1911 and 1918, turning Bear Lake into a reservoir. The prediversion lake had an unusually high Mg2+ :C a2+ ratio (38 by weight), which resulted in precipitation of CaCO3 as aragonite. The amount and mineralogy

  20. Filtration effects on ball bearing life and condition in a contaminated lubricant

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Moyer, D. W.

    1978-01-01

    Ball bearings were fatigue tested with a noncontaminated MIL-L-23699 lubricant and with a contaminated MIL-L-23699 lubricant under four levels of filtration. The test filters had absolute particle removal ratings of 3, 30, 49, and 105 microns. Aircraft turbine engine contaminants were injected into the filter's supply line at a constant rate of 125 milligrams per bearing hour. Bearing life and running track condition generally improved with finer filtration. The experimental lives of 3- and 30-micron filter bearings were statistically equivalent, approaching those obtained with the noncontaminated lubricant bearings. Compared to these bearings, the lives of the 49-micron bearings were statistically lower. The 105-micron bearings experienced gross wear. The degree of surface distress, weight loss, and probable failure mode were dependent on filtration level, with finer filtration being clearly beneficial.

  1. Filtration effects on ball bearing life and condition in a contaminated lubricant

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Moyer, D. W.

    1978-01-01

    Ball bearings were fatigue tested with a noncontaminated lubricant and with a contaminated lubricant under four levels of filtration. The test filters had absolute particle removal ratings of 3, 30, 49, and 105 microns. Aircraft turbine engine contaminants were injected into the filter's supply line at a constant rate of 125 milligrams per bearing hour. Bearing life and running track condition generally improved with finer filtration. The experimental lives of 3 and 30 micron filter bearings were statistically equivalent, approaching those obtained with the noncontaminated lubricant bearings. Compared to these bearings, the lives of the 49 micron bearings were statistically lower. The 105 micron bearings experienced gross wear. The degree of surface distress, weight loss, and probable failure mode were dependent on filtration level, with finer filtration being clearly beneficial.

  2. A new method for evaluating motor control in gait under real-life environmental conditions. Part 2: Gait analysis

    Microsoft Academic Search

    R. Moe-Nilssen

    1998-01-01

    Objective. The validity of assessing balance in gait by measuring balance in standing is questionable. Better methods for measuring balance during walking are therefore needed.Design. It is suggested that the individual will demonstrate adequate postural control by moving a reference point near the body centre of mass (CoM) smoothly towards an intentional goal, even though movements of the extremities show

  3. Guiding task-oriented gait training after stroke or spinal cord injury by means of a biomechanical gait analysis

    Microsoft Academic Search

    Sylvie Nadeau; Cyril Duclos; Laurent Bouyer; Carol L. Richards

    2011-01-01

    To recover the ability to walk is one of the most important goals of persons recovering from a stroke or spinal cord injury (SCI). While a task-oriented approach to gait training is recommended, randomized controlled trials or meta-analyses comparing different methods of delivering training have failed in general to demonstrate the superiority of one approach over the other. The large

  4. Abstract --The Robotic Gait Rehabilitation (RGR) Trainer, was designed and built to target secondary gait deviations in

    E-print Network

    Mavroidis, Constantinos

    Abstract -- The Robotic Gait Rehabilitation (RGR) Trainer, was designed and built to target weakness or trouble moving one side of their body, and require rehabilitation [1]. Walking allows and Rehabilitation, Harvard Medical School and Spaulding Rehabilitation Hospital, Boston, MA, 02114, USA (phone: 617

  5. Intermittent application of hypergravity by centrifugation attenuates disruption of rat gait induced by 2 weeks of simulated microgravity.

    PubMed

    Tajino, Junichi; Ito, Akira; Nagai, Momoko; Zhang, Xiangkai; Yamaguchi, Shoki; Iijima, Hirotaka; Aoyama, Tomoki; Kuroki, Hiroshi

    2015-07-01

    The effects of intermittent hypergravity on gait alterations and hindlimb muscle atrophy in rats induced by 2 weeks of simulated microgravity were investigated. Rats were submitted to hindlimb unloading for 2 weeks (unloading period), followed by 2 weeks of reloading (recovery period). During the unloading period, animals were subjected to the following treatments: (1) free in cages (Control); (2) continuous unloading (UL); (3) released from unloading for 1hour per day (UL+1G); (4) hypergravity for 1h per day using a centrifuge for small animals (UL+2G). The relative weights of muscles to the whole body weight and kinematics properties of hindlimbs during gait were evaluated. UL rats walked with their hindlimbs overextended, and the oscillation of their limb motion had become narrowed and forward-shifted after the unloading period, and this persisted for at least 2 weeks after the termination of unloading. However, these locomotor alterations were attenuated in rats subjected to UL+2G centrifugation despite minor systematic changes in muscle recovery. These findings indicate hypergravity application could counteract the adverse effects of simulated or actual microgravity environments. PMID:25819803

  6. Effects of Gait and Cognitive Task Difficulty on Cognitive-Motor Interference in Aging

    PubMed Central

    Plummer-D'Amato, Prudence; Brancato, Briana; Dantowitz, Mallory; Birken, Stephanie; Bonke, Christina; Furey, Erin

    2012-01-01

    Although gait-related dual-task interference in aging is well established, the effect of gait and cognitive task difficulty on dual-task interference is poorly understood. The purpose of this study was to examine the effect of gait and cognitive task difficulty on cognitive-motor interference in aging. Fifteen older adults (72.1 years, SD 5.2) and 20 young adults (21.7 years, SD 1.6) performed three walking tasks of varying difficulty (self-selected speed, fast speed, and fast speed with obstacle crossing) under single- and dual-task conditions. The cognitive tasks were the auditory Stroop task and the clock task. There was a significant Group × Gait Task × Cognitive Task interaction for the dual-task effect on gait speed. After adjusting for education, there were no significant effects of gait or cognitive task difficulty on the dual-task effects on cognitive task performance. The results of this study provide evidence that gait task difficulty influences dual-task effects on gait speed, especially in older adults. Moreover, the effects of gait task difficulty on dual-task interference appear to be influenced by the difficulty of the cognitive task. Education is an important factor influencing cognitive-motor interference effects on cognition, but not gait. PMID:23209905

  7. Effects of gait and cognitive task difficulty on cognitive-motor interference in aging.

    PubMed

    Plummer-D'Amato, Prudence; Brancato, Briana; Dantowitz, Mallory; Birken, Stephanie; Bonke, Christina; Furey, Erin

    2012-01-01

    Although gait-related dual-task interference in aging is well established, the effect of gait and cognitive task difficulty on dual-task interference is poorly understood. The purpose of this study was to examine the effect of gait and cognitive task difficulty on cognitive-motor interference in aging. Fifteen older adults (72.1 years, SD 5.2) and 20 young adults (21.7 years, SD 1.6) performed three walking tasks of varying difficulty (self-selected speed, fast speed, and fast speed with obstacle crossing) under single- and dual-task conditions. The cognitive tasks were the auditory Stroop task and the clock task. There was a significant Group × Gait Task × Cognitive Task interaction for the dual-task effect on gait speed. After adjusting for education, there were no significant effects of gait or cognitive task difficulty on the dual-task effects on cognitive task performance. The results of this study provide evidence that gait task difficulty influences dual-task effects on gait speed, especially in older adults. Moreover, the effects of gait task difficulty on dual-task interference appear to be influenced by the difficulty of the cognitive task. Education is an important factor influencing cognitive-motor interference effects on cognition, but not gait. PMID:23209905

  8. Sensitivity of spatiotemporal gait parameters in measuring disease severity in Friedreich ataxia.

    PubMed

    Milne, Sarah C; Hocking, Darren R; Georgiou-Karistianis, Nellie; Murphy, Anna; Delatycki, Martin B; Corben, Louise A

    2014-12-01

    Friedreich ataxia (FRDA) is an autosomal recessive disease with gait ataxia being the main source of morbidity. Mobility progressively declines, from initial symptom onset at approximately 10-15 years of age to being unable to ambulate 10-15 years later. Here, we sought to investigate the relationship between spatiotemporal gait parameters and clinical markers of disease severity. Thirteen people with FRDA walked along an 8.3-m GAITRite® mat six times each at their preferred fast and slow speeds. Relationships between spatiotemporal gait parameters and a range of clinical and disease characteristics were examined. Significant correlations were found between spatiotemporal gait characteristics at each of the walking speeds and Friedreich Ataxia Rating Scale (FARS) score and disease duration. During the fast-walking condition, gait speed and cadence decreased with an increase in disease duration and the FARS score. GAA1 repeat expansion negatively correlated with double-support percentage of the gait cycle in all speed conditions demonstrating a relationship between the genetic mutation and compensatory strategies for impaired dynamic balance. In all speed conditions, there were correlations between a range of spatiotemporal gait characteristics and the timed 25-ft walk test, a well-established measure of gait mobility. These findings suggest that spatiotemporal gait parameters are a sensitive measure of gait decline in individuals with FRDA and should be considered for inclusion in intervention studies whilst participants are still ambulant. PMID:25022367

  9. Side of basal ganglia degeneration influences freezing of gait in Parkinson's disease.

    PubMed

    Pieruccini-Faria, Frederico; Ehgoetz Martens, Kaylena A; Silveira, Carolina R A; Jones, Jeffery A; Almeida, Quincy J

    2015-04-01

    Although the role of hemispheric laterality in freezing of gait (FOG) remains a topic of debate, important new evidence has suggested that individuals with Parkinson's disease (PD) who experience freezing of gait (PD-FOG) may have decreased activity in the circuitry of the right fronto-parietal cortices, irrespective of the side of basal ganglia (BG) degeneration. Because the right hemisphere plays an important role in monitoring sensorimotor information during movements, and cortical regions interact with BG loops, one could expect that right cortical dysfunction in PD-FOG might be exacerbated by right sided BG damage (compared to left). The current study aimed to evaluate the influence of asymmetrical BG degeneration on self-paced gait in PD-FOG and PD-nonFOG. This study compared gait performance in predominantly left- or right-side affected PD patients with or without freezing of gait (LFOG = 11, RFOG = 10, LPD = 15, RPD = 11). Participants were instructed to walk 10m on a GaitRite® carpet. As expected, gait parameters in PD-FOG were worse compared to PD-nonFOG. The spatiotemporal aspects of gait did not differ between LPD and RPD (nonFOG patients). Contrary to our hypothesis, RFOG (predominantly right side symptoms) had a shorter step length, increased step time variability and tended to walk slower compared with LFOG. Thus, rather than severely impaired right hemisphere circuitries exacerbating gait impairments, worse gait may be a consequence of both hemispheres being affected in PD-FOG. PMID:25730121

  10. Bearing-Cartridge Damping Seal

    NASA Technical Reports Server (NTRS)

    Goggins, David G.; Scharrer, Joseph K.; Chen, Wei C.

    1991-01-01

    In proposed design for improved ball-bearing cartridge, damping seal in form of thin-layer fluid journal bearing incorporated into cartridge. Damping seal acts as auxiliary bearing, relieving bearing balls of significant portions of both static and dynamic bearing loads. Damping from seal reduces dynamic loads even further by reducing amplitude of vibrations in second vibrational mode of rotor, which mode occurs when rotor turning at nearly full operating speed. Intended for use in high-pressure-oxygen turbopump of Space Shuttle main engine, also applicable to other turbomachinery bearings.

  11. Feasibility of magnetic bearings for advanced gas turbine engines

    NASA Technical Reports Server (NTRS)

    Hibner, David; Rosado, Lewis

    1992-01-01

    The application of active magnetic bearings to advanced gas turbine engines will provide a product with major improvements compared to current oil lubricated bearing designs. A rethinking of the engine rotating and static structure design is necessary and will provide the designer with significantly more freedom to meet the demanding goals of improved performance, increased durability, higher reliability, and increased thrust to weight ratio via engine weight reduction. The product specific technology necessary for this high speed, high temperature, dynamically complex application has been defined. The resulting benefits from this approach to aircraft engine rotor support and the complementary engine changes and improvements have been assessed.

  12. Improved gait adjustments after gait adaptability training are associated with reduced attentional demands in persons with stroke.

    PubMed

    van Ooijen, Mariëlle W; Heeren, Anita; Smulders, Katrijn; Geurts, Alexander C H; Janssen, Thomas W J; Beek, Peter J; Weerdesteyn, Vivian; Roerdink, Melvyn

    2015-03-01

    After stroke, the ability to make step adjustments during walking is reduced and requires more attention, which may cause problems during community walking. The C-Mill is an innovative treadmill augmented with visual context (e.g., obstacles and stepping targets), which was designed specifically to practice gait adaptability. The objective of this study was to determine whether C-Mill gait adaptability training can help to improve gait adjustments and associated attentional demands. Sixteen community-ambulating persons in the chronic stage of stroke (age: 54.8 ± 10.8 years) received ten sessions of C-Mill training within 5-6 weeks. Prior to and after the intervention period, participants performed an obstacle-avoidance task with and without a secondary attention-demanding auditory Stroop task to assess their ability to make gait adjustments (i.e., obstacle-avoidance success rates) as well as the associated attentional demands (i.e., Stroop success rates, stratified for pre-crossing, crossing, and post-crossing strides). Obstacle-avoidance success rates improved after C-Mill training from 52.4 ± 16.3 % at pretest to 77.0 ± 16.4 % at posttest (p < 0.001). This improvement was accompanied by greater Stroop success rates during the obstacle-crossing stride only (pretest: 62.9 ± 24.9 %, posttest: 77.5 ± 20.4 %, p = 0.006). The observed improvements in obstacle-avoidance success rates and Stroop success rates were strongly correlated (r = 0.68, p = 0.015). The ability to make gait adjustments and the associated attentional demands can be successfully targeted in persons with stroke using C-Mill training, which suggests that its underlying assumptions regarding motor control are appropriate. This study lends support and guidance for designing a randomized controlled trial to further examine the potential of C-Mill training for improving safe community ambulation after stroke. PMID:25537466

  13. A Longitudinal Study on Dual-Tasking Effects on Gait: Cognitive Change Predicts Gait Variance in the Elderly

    PubMed Central

    MacAulay, Rebecca K.; Brouillette, Robert M.; Foil, Heather C.; Bruce-Keller, Annadora J.; Keller, Jeffrey N.

    2014-01-01

    Neuropsychological abilities have found to explain a large proportion of variance in objective measures of walking gait that predict both dementia and falling within the elderly. However, to this date there has been little research on the interplay between changes in these neuropsychological processes and walking gait overtime. To our knowledge, the present study is the first to investigate intra-individual changes in neurocognitive test performance and gait step time at two-time points across a one-year span. Neuropsychological test scores from 440 elderly individuals deemed cognitively normal at Year One were analyzed via repeated measures t-tests to assess for decline in cognitive performance at Year Two. 34 of these 440 individuals neuropsychological test performance significantly declined at Year Two; whereas the “non-decliners” displayed improved memory, working memory, attention/processing speed test performance. Neuropsychological test scores were also submitted to factor analysis at both time points for data reduction purposes and to assess the factor stability overtime. Results at Year One yielded a three-factor solution: Language/Memory, Executive Attention/Processing Speed, and Working Memory. Year Two's test scores also generated a three-factor solution (Working Memory, Language/Executive Attention/Processing Speed, and Memory). Notably, language measures loaded on Executive Attention/Processing Speed rather than on the Memory factor at Year Two. Hierarchal multiple regression revealed that both Executive Attention/Processing Speed and sex significantly predicted variance in dual task step time at both time points. Remarkably, in the “decliners”, the magnitude of the contribution of the neuropsychological characteristics to gait variance significantly increased at Year Two. In summary, this study provides longitudinal evidence of the dynamic relationship between intra-individual cognitive change and its influence on dual task gait step time. These results also indicate that the failure to show improved test performance (particularly, on memory tests) with repeated administrations might prove to be useful of indicator of early cognitive decline. PMID:24905590

  14. 10. DETAIL VIEW OF END BEARING CONDITION SHOWING MOVEABLE BEARING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. DETAIL VIEW OF END BEARING CONDITION SHOWING MOVEABLE BEARING AT SOUTHEAST END OF LOWER ROAD LEVEL - Mahoning Avenue Pratt Double-Deck Bridge, Spanning Mill Creek at Mahoning Avenue (C.R. 319), Youngstown, Mahoning County, OH

  15. Tardigrada (Water Bears)

    NSDL National Science Digital Library

    Micrographia

    This reference page offers a brief description of Tardigrades, also known as water bears. It includes information about their physical appearance, an explanation of their name, likely habitats, internal organs and other distinguishing features, and a few images. A diagram of a common tardigrade, Macrobiotus macronyx, is also provided via an internal link.

  16. Magnetic Bearings For Turbopumps

    NASA Technical Reports Server (NTRS)

    Meeks, Crawford R.; Mendez, Antonio J.

    1995-01-01

    Report presents study of feasibility of magnetic bearings in turbopumps. Liquid-oxygen turbopump in space shuttle main engine selected for study. Other potential applications include manned and unmanned spacecraft, gas turbines for commercial and military aircraft, turbomachinery for petro-chemical and gas operations, suspension systems for precise machinery, and precise pointing and tracking systems.

  17. Bear vs Bee

    NSDL National Science Digital Library

    2012-01-01

    This interactive Java applet is a game that challenges a student to solve problems by using logic and rudimentary engineering skills. The goal in each case is to create a conveyance that gets the bear to the pot of honey, avoiding the bees. The game has 32 stages of increasing complexity.

  18. Bearings Incorporating Deadband Rollers

    NASA Technical Reports Server (NTRS)

    Gualtieri, Guy V.

    1996-01-01

    Bearings in high-pressure turbopump redesigned to incorporate rollers allowing limited axial motion within small deadband. Does not permit radial deadband motion. Axial deadband motion used for rotor-thrust-balance control. Design eliminates some nonlinearities in dynamics of pump rotor and assists in suppressing vibrations at harmonics of frequency of rotation.

  19. History of ball bearings

    NASA Technical Reports Server (NTRS)

    Dowson, D.; Hamrock, B. J.

    1981-01-01

    The familiar precision rolling-element bearings of the twentieth century are products of exacting technology and sophisticated science. Their very effectiveness and basic simplicity of form may discourage further interest in their history and development. Yet the full story covers a large portion of recorded history and surprising evidence of an early recognition of the advantages of rolling motion over sliding action and progress toward the development of rolling-element bearings. The development of rolling-element bearings is followed from the earliest civilizations to the end of the eighteenth century. The influence of general technological developments, particularly those concerned with the movement of large building blocks, road transportation, instruments, water-raising equipment, and windmills are discussed, together with the emergence of studies of the nature of rolling friction and the impact of economic factors. By 1800 the essential features of ball and rolling-element bearings had emerged and it only remained for precision manufacture and mass production to confirm the value of these fascinating machine elements.

  20. Oregon Zoo Polar Bear

    USGS Multimedia Gallery

    Tasul, an Oregon Zoo polar bear, sports a high-tech collar that will help researchers study her endangered wild counterparts in the Arctic. Photo by Michael Durham, courtesy of the Oregon Zoo. Photo by Michael Durham, courtesy of the Oregon Zoo....